Game 1 Unit 15 of 64 1 hr learning time

Game States

Add a state machine with title screen, game over, and win states.

23% of Neon Nexus

Mark as complete Completed!

What You’re Building

A complete game flow. Title screen. Playing. Game over. Win.

Game States

The game now starts at a title screen. Press Start to play.

The State Machine

Four states control the game:

STATE_TITLE    = 0
STATE_PLAYING  = 1
STATE_GAMEOVER = 2
STATE_WIN      = 3

Main Loop

The main loop dispatches to state handlers:

main_loop:
    jsr read_controller

    lda game_state
    cmp #STATE_TITLE
    beq @title_state
    cmp #STATE_PLAYING
    beq @playing_state
    cmp #STATE_GAMEOVER
    beq @gameover_state
    cmp #STATE_WIN
    beq @win_state
    jmp main_loop

@title_state:
    jsr handle_title
    jmp main_loop

Each state has its own handler. Clean separation.

Button Edge Detection

We want to detect a new press, not a held button:

BTN_START = %00010000

handle_title:
    lda buttons
    and #BTN_START
    beq @no_start
    lda buttons_prev
    and #BTN_START
    bne @no_start       ; Already pressed

    ; New press! Start the game
    jsr init_game
    lda #STATE_PLAYING
    sta game_state

@no_start:
    lda buttons
    sta buttons_prev
    rts

Compare current buttons with previous frame. Only act on the rising edge.

State Transitions

From	To	Trigger
TITLE	PLAYING	Start pressed
PLAYING	GAMEOVER	Lives reach 0
PLAYING	WIN	All items collected
GAMEOVER	TITLE	Start pressed
WIN	TITLE	Start pressed

Screen Displays

Each state shows different sprites:

Title: Player with decorative items
Playing: Full game (player, enemies, items, lives)
Game Over: Enemy sprites as defeat indicator
Win: Player surrounded by items

The Code

; =============================================================================
; NEON NEXUS - Unit 15: Game States
; =============================================================================
; Add a state machine with title screen, playing, game over, and win states.
; =============================================================================

PPUCTRL   = $2000
PPUMASK   = $2001
PPUSTATUS = $2002
OAMADDR   = $2003
PPUSCROLL = $2005
PPUADDR   = $2006
PPUDATA   = $2007
OAMDMA    = $4014
APUSTATUS = $4015
JOYPAD1   = $4016

; APU Pulse 1 registers
APU_PULSE1_CTRL = $4000
APU_PULSE1_SWEEP = $4001
APU_PULSE1_LO = $4002
APU_PULSE1_HI = $4003

BTN_START  = %00010000
BTN_UP     = %00001000
BTN_DOWN   = %00000100
BTN_LEFT   = %00000010
BTN_RIGHT  = %00000001

; Game states
STATE_TITLE    = 0
STATE_PLAYING  = 1
STATE_GAMEOVER = 2
STATE_WIN      = 3

PLAYER_START_X  = 124
PLAYER_START_Y  = 116
PLAYER_SPEED    = 2
ENEMY_SPEED     = 1
NUM_ENEMIES     = 4
NUM_ITEMS       = 4
STARTING_LIVES  = 3
COLLISION_DIST  = 6
COLLECT_DIST    = 8
INVULN_TIME     = 90

TILE_BORDER    = 1
TILE_FLOOR     = 2
TILE_CORNER_TL = 3
TILE_CORNER_TR = 4
TILE_CORNER_BL = 5
TILE_CORNER_BR = 6
SPRITE_PLAYER  = 7
SPRITE_ENEMY   = 8
SPRITE_LIFE    = 9
SPRITE_ITEM    = 10

ARENA_LEFT   = 16
ARENA_RIGHT  = 232
ARENA_TOP    = 24
ARENA_BOTTOM = 208

DIR_RIGHT = 1
DIR_LEFT  = $FF
DIR_DOWN  = 1
DIR_UP    = $FF
BG_COLOUR = $0F

.segment "ZEROPAGE"
player_x:       .res 1
player_y:       .res 1
buttons:        .res 1
buttons_prev:   .res 1      ; Previous frame buttons (for edge detection)
temp:           .res 1
row_counter:    .res 1
frame_count:    .res 1
lives:          .res 1
invuln_timer:   .res 1
game_state:     .res 1      ; Current game state
items_collected: .res 1
score_lo:       .res 1
score_hi:       .res 1

enemy_x:        .res NUM_ENEMIES
enemy_y:        .res NUM_ENEMIES
enemy_dir_x:    .res NUM_ENEMIES
enemy_dir_y:    .res NUM_ENEMIES

item_x:         .res NUM_ITEMS
item_y:         .res NUM_ITEMS
item_active:    .res NUM_ITEMS

.segment "OAM"
oam_buffer:     .res 256

.segment "BSS"

.segment "HEADER"
    .byte "NES", $1A, 2, 1, $01, $00, 0,0,0,0,0,0,0,0

.segment "CODE"

reset:
    sei
    cld
    ldx #$40
    stx $4017
    ldx #$FF
    txs
    inx
    stx PPUCTRL
    stx PPUMASK
    stx $4010

@vblank1:
    bit PPUSTATUS
    bpl @vblank1

    lda #0
@clear_ram:
    sta $0000, x
    sta $0100, x
    sta $0200, x
    sta $0300, x
    sta $0400, x
    sta $0500, x
    sta $0600, x
    sta $0700, x
    inx
    bne @clear_ram

@vblank2:
    bit PPUSTATUS
    bpl @vblank2

    jsr load_palette
    jsr draw_arena
    jsr set_attributes

    ; Hide all sprites initially
    lda #$FF
    ldx #0
@hide_all:
    sta oam_buffer, x
    inx
    bne @hide_all

    lda #0
    sta PPUSCROLL
    sta PPUSCROLL

    ; Enable APU channels
    lda #%00000001
    sta APUSTATUS

    ; Start in title state
    lda #STATE_TITLE
    sta game_state

    lda #%10000000
    sta PPUCTRL
    lda #%00011110
    sta PPUMASK

; =============================================================================
; Main Loop - State Machine
; =============================================================================
main_loop:
    jsr read_controller

    lda game_state
    cmp #STATE_TITLE
    beq @title_state
    cmp #STATE_PLAYING
    beq @playing_state
    cmp #STATE_GAMEOVER
    beq @gameover_state
    cmp #STATE_WIN
    beq @win_state
    jmp main_loop

@title_state:
    jsr handle_title
    jmp main_loop

@playing_state:
    jsr handle_playing
    jmp main_loop

@gameover_state:
    jsr handle_gameover
    jmp main_loop

@win_state:
    jsr handle_win
    jmp main_loop

; =============================================================================
; State Handlers
; =============================================================================

handle_title:
    ; Show title screen sprites
    jsr show_title_sprites

    ; Check for Start button press (new press only)
    lda buttons
    and #BTN_START
    beq @no_start
    lda buttons_prev
    and #BTN_START
    bne @no_start           ; Already pressed last frame

    ; Start pressed! Begin game
    jsr init_game
    lda #STATE_PLAYING
    sta game_state
    jsr play_collect_sound  ; Start game sound

@no_start:
    ; Store previous buttons
    lda buttons
    sta buttons_prev
    rts

handle_playing:
    jsr move_player
    jsr move_enemies
    jsr check_enemy_collisions
    jsr check_item_collisions
    jsr check_win_condition
    jsr update_all_sprites

    ; Store previous buttons
    lda buttons
    sta buttons_prev
    rts

handle_gameover:
    ; Show game over display
    jsr show_gameover_sprites

    ; Check for Start to restart
    lda buttons
    and #BTN_START
    beq @no_restart
    lda buttons_prev
    and #BTN_START
    bne @no_restart

    ; Restart game
    lda #STATE_TITLE
    sta game_state

@no_restart:
    lda buttons
    sta buttons_prev
    rts

handle_win:
    ; Show win display
    jsr show_win_sprites

    ; Check for Start to restart
    lda buttons
    and #BTN_START
    beq @no_restart
    lda buttons_prev
    and #BTN_START
    bne @no_restart

    ; Back to title
    lda #STATE_TITLE
    sta game_state

@no_restart:
    lda buttons
    sta buttons_prev
    rts

; =============================================================================
; Display Routines
; =============================================================================

show_title_sprites:
    ; Hide all sprites first
    lda #$FF
    ldx #0
@hide_loop:
    sta oam_buffer, x
    inx
    bne @hide_loop

    ; Show player sprite in center as "logo"
    lda #100                ; Y position
    sta oam_buffer+0
    lda #SPRITE_PLAYER
    sta oam_buffer+1
    lda #0
    sta oam_buffer+2
    lda #124                ; X position
    sta oam_buffer+3

    ; Show some items as decoration
    lda #100
    sta oam_buffer+4
    lda #SPRITE_ITEM
    sta oam_buffer+5
    lda #%00000010
    sta oam_buffer+6
    lda #100
    sta oam_buffer+7

    lda #100
    sta oam_buffer+8
    lda #SPRITE_ITEM
    sta oam_buffer+9
    lda #%00000010
    sta oam_buffer+10
    lda #148
    sta oam_buffer+11
    rts

show_gameover_sprites:
    ; Hide all sprites
    lda #$FF
    ldx #0
@hide_loop:
    sta oam_buffer, x
    inx
    bne @hide_loop

    ; Show enemies as "defeat" indicator
    lda #100
    sta oam_buffer+0
    lda #SPRITE_ENEMY
    sta oam_buffer+1
    lda #%00000001
    sta oam_buffer+2
    lda #112
    sta oam_buffer+3

    lda #100
    sta oam_buffer+4
    lda #SPRITE_ENEMY
    sta oam_buffer+5
    lda #%00000001
    sta oam_buffer+6
    lda #128
    sta oam_buffer+7

    lda #100
    sta oam_buffer+8
    lda #SPRITE_ENEMY
    sta oam_buffer+9
    lda #%00000001
    sta oam_buffer+10
    lda #144
    sta oam_buffer+11
    rts

show_win_sprites:
    ; Hide all sprites
    lda #$FF
    ldx #0
@hide_loop:
    sta oam_buffer, x
    inx
    bne @hide_loop

    ; Show player and items as "victory" indicator
    lda #100
    sta oam_buffer+0
    lda #SPRITE_PLAYER
    sta oam_buffer+1
    lda #0
    sta oam_buffer+2
    lda #124
    sta oam_buffer+3

    ; Items around player
    lda #92
    sta oam_buffer+4
    lda #SPRITE_ITEM
    sta oam_buffer+5
    lda #%00000010
    sta oam_buffer+6
    lda #116
    sta oam_buffer+7

    lda #92
    sta oam_buffer+8
    lda #SPRITE_ITEM
    sta oam_buffer+9
    lda #%00000010
    sta oam_buffer+10
    lda #132
    sta oam_buffer+11

    lda #108
    sta oam_buffer+12
    lda #SPRITE_ITEM
    sta oam_buffer+13
    lda #%00000010
    sta oam_buffer+14
    lda #116
    sta oam_buffer+15

    lda #108
    sta oam_buffer+16
    lda #SPRITE_ITEM
    sta oam_buffer+17
    lda #%00000010
    sta oam_buffer+18
    lda #132
    sta oam_buffer+19
    rts

; =============================================================================
; Game Initialisation
; =============================================================================

init_game:
    lda #STARTING_LIVES
    sta lives
    lda #0
    sta invuln_timer
    sta items_collected
    sta score_lo
    sta score_hi

    lda #PLAYER_START_X
    sta player_x
    lda #PLAYER_START_Y
    sta player_y

    jsr init_enemies
    jsr init_items
    rts

init_enemies:
    lda #48
    sta enemy_x+0
    sta enemy_y+0
    lda #DIR_RIGHT
    sta enemy_dir_x+0
    lda #DIR_DOWN
    sta enemy_dir_y+0

    lda #200
    sta enemy_x+1
    lda #48
    sta enemy_y+1
    lda #DIR_LEFT
    sta enemy_dir_x+1
    lda #DIR_DOWN
    sta enemy_dir_y+1

    lda #48
    sta enemy_x+2
    lda #176
    sta enemy_y+2
    lda #DIR_RIGHT
    sta enemy_dir_x+2
    lda #DIR_UP
    sta enemy_dir_y+2

    lda #200
    sta enemy_x+3
    lda #176
    sta enemy_y+3
    lda #DIR_LEFT
    sta enemy_dir_x+3
    lda #DIR_UP
    sta enemy_dir_y+3
    rts

init_items:
    lda #80
    sta item_x+0
    lda #64
    sta item_y+0
    lda #1
    sta item_active+0

    lda #168
    sta item_x+1
    lda #64
    sta item_y+1
    lda #1
    sta item_active+1

    lda #80
    sta item_x+2
    lda #160
    sta item_y+2
    lda #1
    sta item_active+2

    lda #168
    sta item_x+3
    lda #160
    sta item_y+3
    lda #1
    sta item_active+3
    rts

; =============================================================================
; Collision Detection
; =============================================================================

check_enemy_collisions:
    lda invuln_timer
    beq @check
    dec invuln_timer
    rts

@check:
    ldx #0
@check_enemy:
    lda player_x
    sec
    sbc enemy_x, x
    bpl @check_x_pos
    eor #$FF
    clc
    adc #1
@check_x_pos:
    cmp #COLLISION_DIST
    bcs @next_enemy

    lda player_y
    sec
    sbc enemy_y, x
    bpl @check_y_pos
    eor #$FF
    clc
    adc #1
@check_y_pos:
    cmp #COLLISION_DIST
    bcs @next_enemy

    jsr player_hit
    rts

@next_enemy:
    inx
    cpx #NUM_ENEMIES
    bne @check_enemy
    rts

check_item_collisions:
    ldx #0
@check_item:
    lda item_active, x
    beq @next_item

    lda player_x
    sec
    sbc item_x, x
    bpl @item_x_pos
    eor #$FF
    clc
    adc #1
@item_x_pos:
    cmp #COLLECT_DIST
    bcs @next_item

    lda player_y
    sec
    sbc item_y, x
    bpl @item_y_pos
    eor #$FF
    clc
    adc #1
@item_y_pos:
    cmp #COLLECT_DIST
    bcs @next_item

    ; Collected!
    lda #0
    sta item_active, x
    inc items_collected
    lda score_lo
    clc
    adc #100
    sta score_lo
    lda score_hi
    adc #0
    sta score_hi
    jsr play_collect_sound

@next_item:
    inx
    cpx #NUM_ITEMS
    bne @check_item
    rts

player_hit:
    jsr play_death_sound
    dec lives
    lda lives
    beq @game_over

    lda #PLAYER_START_X
    sta player_x
    lda #PLAYER_START_Y
    sta player_y

    lda #INVULN_TIME
    sta invuln_timer
    rts

@game_over:
    lda #STATE_GAMEOVER
    sta game_state
    rts

; =============================================================================
; Win Condition
; =============================================================================

check_win_condition:
    lda items_collected
    cmp #NUM_ITEMS
    bne @not_yet
    lda game_state
    cmp #STATE_WIN
    beq @not_yet            ; Already won
    lda #STATE_WIN
    sta game_state
    jsr play_victory_sound
@not_yet:
    rts

; =============================================================================
; Sound Effects
; =============================================================================

play_collect_sound:
    lda #%10011111
    sta APU_PULSE1_CTRL
    lda #0
    sta APU_PULSE1_SWEEP
    lda #$C4
    sta APU_PULSE1_LO
    lda #%00001000
    sta APU_PULSE1_HI
    rts

play_death_sound:
    lda #%10011111
    sta APU_PULSE1_CTRL
    lda #%10001111
    sta APU_PULSE1_SWEEP
    lda #$00
    sta APU_PULSE1_LO
    lda #%00001011
    sta APU_PULSE1_HI
    rts

play_victory_sound:
    lda #%10011111
    sta APU_PULSE1_CTRL
    lda #%10000111
    sta APU_PULSE1_SWEEP
    lda #$FF
    sta APU_PULSE1_LO
    lda #%00000011
    sta APU_PULSE1_HI
    rts

; =============================================================================
; Sprite Updates
; =============================================================================

update_all_sprites:
    jsr update_player_sprite
    jsr update_enemy_sprites
    jsr update_item_sprites
    jsr update_lives_display
    rts

update_player_sprite:
    lda game_state
    cmp #STATE_PLAYING
    bne @hide

    lda invuln_timer
    beq @show
    and #%00000100
    beq @show

@hide:
    lda #$FF
    sta oam_buffer+0
    rts

@show:
    lda player_y
    sta oam_buffer+0
    lda #SPRITE_PLAYER
    sta oam_buffer+1
    lda #0
    sta oam_buffer+2
    lda player_x
    sta oam_buffer+3
    rts

update_enemy_sprites:
    ldx #0
    ldy #4
@loop:
    lda enemy_y, x
    sta oam_buffer, y
    iny
    lda #SPRITE_ENEMY
    sta oam_buffer, y
    iny
    lda #%00000001
    sta oam_buffer, y
    iny
    lda enemy_x, x
    sta oam_buffer, y
    iny
    inx
    cpx #NUM_ENEMIES
    bne @loop
    rts

update_item_sprites:
    ldx #0
    ldy #20
@loop:
    lda item_active, x
    beq @hide_item

    lda item_y, x
    sta oam_buffer, y
    iny
    lda #SPRITE_ITEM
    sta oam_buffer, y
    iny
    lda #%00000010
    sta oam_buffer, y
    iny
    lda item_x, x
    sta oam_buffer, y
    iny
    jmp @next_item

@hide_item:
    lda #$FF
    sta oam_buffer, y
    iny
    iny
    iny
    iny

@next_item:
    inx
    cpx #NUM_ITEMS
    bne @loop
    rts

update_lives_display:
    ldy #36
    ldx lives
    beq @hide_all

    lda #8
    sta oam_buffer, y
    iny
    lda #SPRITE_LIFE
    sta oam_buffer, y
    iny
    lda #0
    sta oam_buffer, y
    iny
    lda #16
    sta oam_buffer, y
    iny

    cpx #1
    beq @hide_rest

    lda #8
    sta oam_buffer, y
    iny
    lda #SPRITE_LIFE
    sta oam_buffer, y
    iny
    lda #0
    sta oam_buffer, y
    iny
    lda #26
    sta oam_buffer, y
    iny

    cpx #2
    beq @hide_rest

    lda #8
    sta oam_buffer, y
    iny
    lda #SPRITE_LIFE
    sta oam_buffer, y
    iny
    lda #0
    sta oam_buffer, y
    iny
    lda #36
    sta oam_buffer, y
    rts

@hide_rest:
@hide_all:
    rts

; =============================================================================
; Enemy Movement
; =============================================================================

move_enemies:
    ldx #0
@enemy_loop:
    lda enemy_x, x
    clc
    adc enemy_dir_x, x
    sta enemy_x, x
    cmp #ARENA_LEFT
    bcs @check_right
    lda #DIR_RIGHT
    sta enemy_dir_x, x
    lda #ARENA_LEFT
    sta enemy_x, x
    jmp @move_y
@check_right:
    cmp #ARENA_RIGHT
    bcc @move_y
    lda #DIR_LEFT
    sta enemy_dir_x, x
    lda #ARENA_RIGHT
    sec
    sbc #1
    sta enemy_x, x
@move_y:
    lda enemy_y, x
    clc
    adc enemy_dir_y, x
    sta enemy_y, x
    cmp #ARENA_TOP
    bcs @check_bottom
    lda #DIR_DOWN
    sta enemy_dir_y, x
    lda #ARENA_TOP
    sta enemy_y, x
    jmp @next_enemy
@check_bottom:
    cmp #ARENA_BOTTOM
    bcc @next_enemy
    lda #DIR_UP
    sta enemy_dir_y, x
    lda #ARENA_BOTTOM
    sec
    sbc #1
    sta enemy_y, x
@next_enemy:
    inx
    cpx #NUM_ENEMIES
    bne @enemy_loop
    rts

; =============================================================================
; PPU Setup
; =============================================================================

load_palette:
    bit PPUSTATUS
    lda #$3F
    sta PPUADDR
    lda #$00
    sta PPUADDR
    ldx #0
@loop:
    lda palette_data, x
    sta PPUDATA
    inx
    cpx #32
    bne @loop
    rts

draw_arena:
    bit PPUSTATUS
    lda #$20
    sta PPUADDR
    lda #$00
    sta PPUADDR
    lda #0
    sta row_counter
@draw_row:
    lda row_counter
    cmp #0
    beq @top_row
    cmp #1
    beq @top_row
    cmp #28
    beq @bottom_row
    cmp #29
    beq @bottom_row
    jmp @middle_row
@top_row:
    lda row_counter
    cmp #0
    bne @top_row_inner
    lda #TILE_CORNER_TL
    sta PPUDATA
    lda #TILE_BORDER
    ldx #30
@top_fill:
    sta PPUDATA
    dex
    bne @top_fill
    lda #TILE_CORNER_TR
    sta PPUDATA
    jmp @next_row
@top_row_inner:
    lda #TILE_BORDER
    ldx #32
@top_inner_fill:
    sta PPUDATA
    dex
    bne @top_inner_fill
    jmp @next_row
@bottom_row:
    lda row_counter
    cmp #29
    bne @bottom_row_inner
    lda #TILE_CORNER_BL
    sta PPUDATA
    lda #TILE_BORDER
    ldx #30
@bottom_fill:
    sta PPUDATA
    dex
    bne @bottom_fill
    lda #TILE_CORNER_BR
    sta PPUDATA
    jmp @next_row
@bottom_row_inner:
    lda #TILE_BORDER
    ldx #32
@bottom_inner_fill:
    sta PPUDATA
    dex
    bne @bottom_inner_fill
    jmp @next_row
@middle_row:
    lda #TILE_BORDER
    sta PPUDATA
    sta PPUDATA
    lda #TILE_FLOOR
    ldx #28
@floor_fill:
    sta PPUDATA
    dex
    bne @floor_fill
    lda #TILE_BORDER
    sta PPUDATA
    sta PPUDATA
@next_row:
    inc row_counter
    lda row_counter
    cmp #30
    beq @done_drawing
    jmp @draw_row
@done_drawing:
    rts

set_attributes:
    bit PPUSTATUS
    lda #$23
    sta PPUADDR
    lda #$C0
    sta PPUADDR
    ldx #8
    lda #$00
@attr_top:
    sta PPUDATA
    dex
    bne @attr_top
    ldx #6
@attr_floor:
    lda #$00
    sta PPUDATA
    lda #%01010101
    sta PPUDATA
    sta PPUDATA
    sta PPUDATA
    sta PPUDATA
    sta PPUDATA
    sta PPUDATA
    lda #$00
    sta PPUDATA
    dex
    bne @attr_floor
    ldx #8
    lda #$00
@attr_bottom:
    sta PPUDATA
    dex
    bne @attr_bottom
    rts

; =============================================================================
; Input
; =============================================================================

read_controller:
    lda #1
    sta JOYPAD1
    lda #0
    sta JOYPAD1
    ldx #8
@read_loop:
    lda JOYPAD1
    lsr a
    rol buttons
    dex
    bne @read_loop
    rts

move_player:
    lda buttons
    and #BTN_UP
    beq @check_down
    lda player_y
    sec
    sbc #PLAYER_SPEED
    cmp #ARENA_TOP
    bcc @check_down
    sta player_y
@check_down:
    lda buttons
    and #BTN_DOWN
    beq @check_left
    lda player_y
    clc
    adc #PLAYER_SPEED
    cmp #ARENA_BOTTOM
    bcs @check_left
    sta player_y
@check_left:
    lda buttons
    and #BTN_LEFT
    beq @check_right
    lda player_x
    sec
    sbc #PLAYER_SPEED
    cmp #ARENA_LEFT
    bcc @check_right
    sta player_x
@check_right:
    lda buttons
    and #BTN_RIGHT
    beq @done
    lda player_x
    clc
    adc #PLAYER_SPEED
    cmp #ARENA_RIGHT
    bcs @done
    sta player_x
@done:
    rts

; =============================================================================
; NMI Handler
; =============================================================================

nmi:
    pha
    txa
    pha
    tya
    pha
    lda #0
    sta OAMADDR
    lda #>oam_buffer
    sta OAMDMA
    inc frame_count
    lda #0
    sta PPUSCROLL
    sta PPUSCROLL
    pla
    tay
    pla
    tax
    pla
    rti

irq:
    rti

; =============================================================================
; Data
; =============================================================================

palette_data:
    .byte BG_COLOUR, $11, $21, $31
    .byte BG_COLOUR, $13, $23, $33
    .byte BG_COLOUR, $19, $29, $39
    .byte BG_COLOUR, $16, $26, $36
    .byte BG_COLOUR, $30, $27, $17    ; Player
    .byte BG_COLOUR, $16, $26, $36    ; Enemies
    .byte BG_COLOUR, $1A, $2A, $3A    ; Items (green)
    .byte BG_COLOUR, $30, $27, $17

.segment "VECTORS"
    .word nmi
    .word reset
    .word irq

.segment "CHARS"
; Tile 0: Empty
.byte $00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00
; Tile 1: Border
.byte %11111111,%10000001,%10000001,%11111111,%11111111,%00010001,%00010001,%11111111
.byte %00000000,%01111110,%01111110,%00000000,%00000000,%11101110,%11101110,%00000000
; Tile 2: Floor
.byte %00000000,%00000000,%00000000,%00000000,%00000000,%00000000,%00000000,%10000001
.byte %00000000,%00000000,%00000000,%00000000,%00000000,%00000000,%00000000,%00000000
; Tile 3: Corner TL
.byte %11111111,%11000000,%10100000,%10010000,%10001000,%10000100,%10000010,%10000001
.byte %00000000,%00111111,%01011111,%01101111,%01110111,%01111011,%01111101,%01111110
; Tile 4: Corner TR
.byte %11111111,%00000011,%00000101,%00001001,%00010001,%00100001,%01000001,%10000001
.byte %00000000,%11111100,%11111010,%11110110,%11101110,%11011110,%10111110,%01111110
; Tile 5: Corner BL
.byte %10000001,%10000010,%10000100,%10001000,%10010000,%10100000,%11000000,%11111111
.byte %01111110,%01111101,%01111011,%01110111,%01101111,%01011111,%00111111,%00000000
; Tile 6: Corner BR
.byte %10000001,%01000001,%00100001,%00010001,%00001001,%00000101,%00000011,%11111111
.byte %01111110,%10111110,%11011110,%11101110,%11110110,%11111010,%11111100,%00000000
; Tile 7: Player (sprite)
.byte %00011000,%00011000,%00111100,%01111110,%11111111,%10111101,%00100100,%00100100
.byte %00000000,%00011000,%00011000,%00111100,%01000010,%01000010,%00011000,%00000000
; Tile 8: Enemy (sprite)
.byte %00011000,%00111100,%01111110,%11111111,%11111111,%01111110,%00111100,%00011000
.byte %00000000,%00011000,%00100100,%01000010,%01000010,%00100100,%00011000,%00000000
; Tile 9: Life icon (sprite)
.byte %00000000,%00100100,%01111110,%01111110,%00111100,%00011000,%00000000,%00000000
.byte %00000000,%00000000,%00000000,%00100100,%00011000,%00000000,%00000000,%00000000
; Tile 10: Item (data core - diamond)
.byte %00000000,%00011000,%00111100,%01111110,%01111110,%00111100,%00011000,%00000000
.byte %00000000,%00000000,%00011000,%00100100,%00100100,%00011000,%00000000,%00000000

.res 8192 - 176, $00

Build It

ca65 nexus.asm -o nexus.o
ld65 -C nes.cfg nexus.o -o nexus.nes

The game now has complete flow. Title, play, end, restart.

Unit 16 brings Phase 1 to a close. Time to review what we’ve built.

What Changed

Unit 14 → Unit 15

+346-67

1	1		`; =============================================================================`
2		-	`; NEON NEXUS - Unit 14: Win Condition`
	2	+	`; NEON NEXUS - Unit 15: Game States`
3	3		`; =============================================================================`
4		-	`; Add a win condition - collecting all items completes the level.`
	4	+	`; Add a state machine with title screen, playing, game over, and win states.`
5	5		`; =============================================================================`
6	6
7	7		`PPUCTRL = $2000`
			...
21	21		`APU_PULSE1_LO = $4002`
22	22		`APU_PULSE1_HI = $4003`
23	23
	24	+	`BTN_START = %00010000`
24	25		`BTN_UP = %00001000`
25	26		`BTN_DOWN = %00000100`
26	27		`BTN_LEFT = %00000010`
27	28		`BTN_RIGHT = %00000001`
	29	+
	30	+	`; Game states`
	31	+	`STATE_TITLE = 0`
	32	+	`STATE_PLAYING = 1`
	33	+	`STATE_GAMEOVER = 2`
	34	+	`STATE_WIN = 3`
28	35
29	36		`PLAYER_START_X = 124`
30	37		`PLAYER_START_Y = 116`
			...
63	70		`player_x: .res 1`
64	71		`player_y: .res 1`
65	72		`buttons: .res 1`
	73	+	`buttons_prev: .res 1 ; Previous frame buttons (for edge detection)`
66	74		`temp: .res 1`
67	75		`row_counter: .res 1`
68	76		`frame_count: .res 1`
69	77		`lives: .res 1`
70	78		`invuln_timer: .res 1`
71		-	`game_over: .res 1`
	79	+	`game_state: .res 1 ; Current game state`
72	80		`items_collected: .res 1`
73		-	`score_lo: .res 1 ; Score low byte`
74		-	`score_hi: .res 1 ; Score high byte (for scores > 255)`
75		-	`level_complete: .res 1 ; Non-zero when all items collected`
	81	+	`score_lo: .res 1`
	82	+	`score_hi: .res 1`
76	83
77	84		`enemy_x: .res NUM_ENEMIES`
78	85		`enemy_y: .res NUM_ENEMIES`
			...
81	88
82	89		`item_x: .res NUM_ITEMS`
83	90		`item_y: .res NUM_ITEMS`
84		-	`item_active: .res NUM_ITEMS ; Non-zero if item exists`
	91	+	`item_active: .res NUM_ITEMS`
85	92
86	93		`.segment "OAM"`
87	94		`oam_buffer: .res 256`
			...
129	136		`jsr load_palette`
130	137		`jsr draw_arena`
131	138		`jsr set_attributes`
132		-	`jsr init_game`
133	139
	140	+	`; Hide all sprites initially`
134	141		`lda #$FF`
135	142		`ldx #0`
136	143		`@hide_all:`
137	144		`sta oam_buffer, x`
138	145		`inx`
139	146		`bne @hide_all`
140		-
141		-	`jsr update_all_sprites`
142	147
143	148		`lda #0`
144	149		`sta PPUSCROLL`
145	150		`sta PPUSCROLL`
146	151
147	152		`; Enable APU channels`
148		-	`lda #%00000001 ; Enable pulse 1`
	153	+	`lda #%00000001`
149	154		`sta APUSTATUS`
	155	+
	156	+	`; Start in title state`
	157	+	`lda #STATE_TITLE`
	158	+	`sta game_state`
150	159
151	160		`lda #%10000000`
152	161		`sta PPUCTRL`
153	162		`lda #%00011110`
154	163		`sta PPUMASK`
155	164
	165	+	`; =============================================================================`
	166	+	`; Main Loop - State Machine`
	167	+	`; =============================================================================`
156	168		`main_loop:`
157		-	`lda game_over`
158		-	`bne @game_over_loop`
159		-	`lda level_complete`
160		-	`bne @level_complete_loop`
161	169		`jsr read_controller`
	170	+
	171	+	`lda game_state`
	172	+	`cmp #STATE_TITLE`
	173	+	`beq @title_state`
	174	+	`cmp #STATE_PLAYING`
	175	+	`beq @playing_state`
	176	+	`cmp #STATE_GAMEOVER`
	177	+	`beq @gameover_state`
	178	+	`cmp #STATE_WIN`
	179	+	`beq @win_state`
	180	+	`jmp main_loop`
	181	+
	182	+	`@title_state:`
	183	+	`jsr handle_title`
	184	+	`jmp main_loop`
	185	+
	186	+	`@playing_state:`
	187	+	`jsr handle_playing`
	188	+	`jmp main_loop`
	189	+
	190	+	`@gameover_state:`
	191	+	`jsr handle_gameover`
	192	+	`jmp main_loop`
	193	+
	194	+	`@win_state:`
	195	+	`jsr handle_win`
	196	+	`jmp main_loop`
	197	+
	198	+	`; =============================================================================`
	199	+	`; State Handlers`
	200	+	`; =============================================================================`
	201	+
	202	+	`handle_title:`
	203	+	`; Show title screen sprites`
	204	+	`jsr show_title_sprites`
	205	+
	206	+	`; Check for Start button press (new press only)`
	207	+	`lda buttons`
	208	+	`and #BTN_START`
	209	+	`beq @no_start`
	210	+	`lda buttons_prev`
	211	+	`and #BTN_START`
	212	+	`bne @no_start ; Already pressed last frame`
	213	+
	214	+	`; Start pressed! Begin game`
	215	+	`jsr init_game`
	216	+	`lda #STATE_PLAYING`
	217	+	`sta game_state`
	218	+	`jsr play_collect_sound ; Start game sound`
	219	+
	220	+	`@no_start:`
	221	+	`; Store previous buttons`
	222	+	`lda buttons`
	223	+	`sta buttons_prev`
	224	+	`rts`
	225	+
	226	+	`handle_playing:`
162	227		`jsr move_player`
163	228		`jsr move_enemies`
164	229		`jsr check_enemy_collisions`
165	230		`jsr check_item_collisions`
166	231		`jsr check_win_condition`
167	232		`jsr update_all_sprites`
168		-	`jmp main_loop`
169	233
170		-	`@game_over_loop:`
171		-	`jmp @game_over_loop`
	234	+	`; Store previous buttons`
	235	+	`lda buttons`
	236	+	`sta buttons_prev`
	237	+	`rts`
172	238
173		-	`@level_complete_loop:`
174		-	`jsr update_all_sprites ; Keep showing win state`
175		-	`jmp @level_complete_loop`
	239	+	`handle_gameover:`
	240	+	`; Show game over display`
	241	+	`jsr show_gameover_sprites`
	242	+
	243	+	`; Check for Start to restart`
	244	+	`lda buttons`
	245	+	`and #BTN_START`
	246	+	`beq @no_restart`
	247	+	`lda buttons_prev`
	248	+	`and #BTN_START`
	249	+	`bne @no_restart`
	250	+
	251	+	`; Restart game`
	252	+	`lda #STATE_TITLE`
	253	+	`sta game_state`
	254	+
	255	+	`@no_restart:`
	256	+	`lda buttons`
	257	+	`sta buttons_prev`
	258	+	`rts`
	259	+
	260	+	`handle_win:`
	261	+	`; Show win display`
	262	+	`jsr show_win_sprites`
	263	+
	264	+	`; Check for Start to restart`
	265	+	`lda buttons`
	266	+	`and #BTN_START`
	267	+	`beq @no_restart`
	268	+	`lda buttons_prev`
	269	+	`and #BTN_START`
	270	+	`bne @no_restart`
	271	+
	272	+	`; Back to title`
	273	+	`lda #STATE_TITLE`
	274	+	`sta game_state`
	275	+
	276	+	`@no_restart:`
	277	+	`lda buttons`
	278	+	`sta buttons_prev`
	279	+	`rts`
	280	+
	281	+	`; =============================================================================`
	282	+	`; Display Routines`
	283	+	`; =============================================================================`
	284	+
	285	+	`show_title_sprites:`
	286	+	`; Hide all sprites first`
	287	+	`lda #$FF`
	288	+	`ldx #0`
	289	+	`@hide_loop:`
	290	+	`sta oam_buffer, x`
	291	+	`inx`
	292	+	`bne @hide_loop`
	293	+
	294	+	`; Show player sprite in center as "logo"`
	295	+	`lda #100 ; Y position`
	296	+	`sta oam_buffer+0`
	297	+	`lda #SPRITE_PLAYER`
	298	+	`sta oam_buffer+1`
	299	+	`lda #0`
	300	+	`sta oam_buffer+2`
	301	+	`lda #124 ; X position`
	302	+	`sta oam_buffer+3`
	303	+
	304	+	`; Show some items as decoration`
	305	+	`lda #100`
	306	+	`sta oam_buffer+4`
	307	+	`lda #SPRITE_ITEM`
	308	+	`sta oam_buffer+5`
	309	+	`lda #%00000010`
	310	+	`sta oam_buffer+6`
	311	+	`lda #100`
	312	+	`sta oam_buffer+7`
	313	+
	314	+	`lda #100`
	315	+	`sta oam_buffer+8`
	316	+	`lda #SPRITE_ITEM`
	317	+	`sta oam_buffer+9`
	318	+	`lda #%00000010`
	319	+	`sta oam_buffer+10`
	320	+	`lda #148`
	321	+	`sta oam_buffer+11`
	322	+	`rts`
	323	+
	324	+	`show_gameover_sprites:`
	325	+	`; Hide all sprites`
	326	+	`lda #$FF`
	327	+	`ldx #0`
	328	+	`@hide_loop:`
	329	+	`sta oam_buffer, x`
	330	+	`inx`
	331	+	`bne @hide_loop`
	332	+
	333	+	`; Show enemies as "defeat" indicator`
	334	+	`lda #100`
	335	+	`sta oam_buffer+0`
	336	+	`lda #SPRITE_ENEMY`
	337	+	`sta oam_buffer+1`
	338	+	`lda #%00000001`
	339	+	`sta oam_buffer+2`
	340	+	`lda #112`
	341	+	`sta oam_buffer+3`
	342	+
	343	+	`lda #100`
	344	+	`sta oam_buffer+4`
	345	+	`lda #SPRITE_ENEMY`
	346	+	`sta oam_buffer+5`
	347	+	`lda #%00000001`
	348	+	`sta oam_buffer+6`
	349	+	`lda #128`
	350	+	`sta oam_buffer+7`
	351	+
	352	+	`lda #100`
	353	+	`sta oam_buffer+8`
	354	+	`lda #SPRITE_ENEMY`
	355	+	`sta oam_buffer+9`
	356	+	`lda #%00000001`
	357	+	`sta oam_buffer+10`
	358	+	`lda #144`
	359	+	`sta oam_buffer+11`
	360	+	`rts`
	361	+
	362	+	`show_win_sprites:`
	363	+	`; Hide all sprites`
	364	+	`lda #$FF`
	365	+	`ldx #0`
	366	+	`@hide_loop:`
	367	+	`sta oam_buffer, x`
	368	+	`inx`
	369	+	`bne @hide_loop`
	370	+
	371	+	`; Show player and items as "victory" indicator`
	372	+	`lda #100`
	373	+	`sta oam_buffer+0`
	374	+	`lda #SPRITE_PLAYER`
	375	+	`sta oam_buffer+1`
	376	+	`lda #0`
	377	+	`sta oam_buffer+2`
	378	+	`lda #124`
	379	+	`sta oam_buffer+3`
	380	+
	381	+	`; Items around player`
	382	+	`lda #92`
	383	+	`sta oam_buffer+4`
	384	+	`lda #SPRITE_ITEM`
	385	+	`sta oam_buffer+5`
	386	+	`lda #%00000010`
	387	+	`sta oam_buffer+6`
	388	+	`lda #116`
	389	+	`sta oam_buffer+7`
	390	+
	391	+	`lda #92`
	392	+	`sta oam_buffer+8`
	393	+	`lda #SPRITE_ITEM`
	394	+	`sta oam_buffer+9`
	395	+	`lda #%00000010`
	396	+	`sta oam_buffer+10`
	397	+	`lda #132`
	398	+	`sta oam_buffer+11`
	399	+
	400	+	`lda #108`
	401	+	`sta oam_buffer+12`
	402	+	`lda #SPRITE_ITEM`
	403	+	`sta oam_buffer+13`
	404	+	`lda #%00000010`
	405	+	`sta oam_buffer+14`
	406	+	`lda #116`
	407	+	`sta oam_buffer+15`
	408	+
	409	+	`lda #108`
	410	+	`sta oam_buffer+16`
	411	+	`lda #SPRITE_ITEM`
	412	+	`sta oam_buffer+17`
	413	+	`lda #%00000010`
	414	+	`sta oam_buffer+18`
	415	+	`lda #132`
	416	+	`sta oam_buffer+19`
	417	+	`rts`
	418	+
	419	+	`; =============================================================================`
	420	+	`; Game Initialisation`
	421	+	`; =============================================================================`
176	422
177	423		`init_game:`
178	424		`lda #STARTING_LIVES`
179	425		`sta lives`
180	426		`lda #0`
181		-	`sta game_over`
182		-	`sta level_complete`
183	427		`sta invuln_timer`
184	428		`sta items_collected`
185	429		`sta score_lo`
			...
232	476		`rts`
233	477
234	478		`init_items:`
235		-	`; Place 4 items around the arena`
236	479		`lda #80`
237	480		`sta item_x+0`
238	481		`lda #64`
			...
261	504		`lda #1`
262	505		`sta item_active+3`
263	506		`rts`
	507	+
	508	+	`; =============================================================================`
	509	+	`; Collision Detection`
	510	+	`; =============================================================================`
264	511
265	512		`check_enemy_collisions:`
266	513		`lda invuln_timer`
			...
330	577		`cmp #COLLECT_DIST`
331	578		`bcs @next_item`
332	579
333		-	`; Collected! Add 100 points`
	580	+	`; Collected!`
334	581		`lda #0`
335	582		`sta item_active, x`
336	583		`inc items_collected`
337		-	`; Add 100 to score (100 = $64)`
338	584		`lda score_lo`
339	585		`clc`
340	586		`adc #100`
			...
366	612		`rts`
367	613
368	614		`@game_over:`
369		-	`lda #1`
370		-	`sta game_over`
	615	+	`lda #STATE_GAMEOVER`
	616	+	`sta game_state`
371	617		`rts`
372	618
373		-	`; -----------------------------------------------------------------------------`
	619	+	`; =============================================================================`
	620	+	`; Win Condition`
	621	+	`; =============================================================================`
	622	+
	623	+	`check_win_condition:`
	624	+	`lda items_collected`
	625	+	`cmp #NUM_ITEMS`
	626	+	`bne @not_yet`
	627	+	`lda game_state`
	628	+	`cmp #STATE_WIN`
	629	+	`beq @not_yet ; Already won`
	630	+	`lda #STATE_WIN`
	631	+	`sta game_state`
	632	+	`jsr play_victory_sound`
	633	+	`@not_yet:`
	634	+	`rts`
	635	+
	636	+	`; =============================================================================`
374	637		`; Sound Effects`
375		-	`; -----------------------------------------------------------------------------`
	638	+	`; =============================================================================`
	639	+
376	640		`play_collect_sound:`
377		-	`; High-pitched short beep`
378		-	`lda #%10011111 ; Duty 50%, length counter disabled, constant vol, vol 15`
	641	+	`lda #%10011111`
379	642		`sta APU_PULSE1_CTRL`
380	643		`lda #0`
381	644		`sta APU_PULSE1_SWEEP`
382		-	`lda #$C4 ; Low byte of period (high pitch)`
	645	+	`lda #$C4`
383	646		`sta APU_PULSE1_LO`
384		-	`lda #%00001000 ; Length counter load, high bits of period`
	647	+	`lda #%00001000`
385	648		`sta APU_PULSE1_HI`
386	649		`rts`
387	650
388	651		`play_death_sound:`
389		-	`; Low-pitched descending sound`
390		-	`lda #%10011111 ; Duty 50%, constant vol, vol 15`
	652	+	`lda #%10011111`
391	653		`sta APU_PULSE1_CTRL`
392		-	`lda #%10001111 ; Sweep enabled, down, fast`
	654	+	`lda #%10001111`
393	655		`sta APU_PULSE1_SWEEP`
394		-	`lda #$00 ; Low byte of period (low pitch)`
	656	+	`lda #$00`
395	657		`sta APU_PULSE1_LO`
396		-	`lda #%00001011 ; Length counter load, high bits`
	658	+	`lda #%00001011`
397	659		`sta APU_PULSE1_HI`
398	660		`rts`
399	661
400	662		`play_victory_sound:`
401		-	`; Ascending triumphant sound`
402		-	`lda #%10011111 ; Duty 50%, constant vol, vol 15`
	663	+	`lda #%10011111`
403	664		`sta APU_PULSE1_CTRL`
404		-	`lda #%10000111 ; Sweep enabled, up, fast`
	665	+	`lda #%10000111`
405	666		`sta APU_PULSE1_SWEEP`
406		-	`lda #$FF ; Low byte of period (start low)`
	667	+	`lda #$FF`
407	668		`sta APU_PULSE1_LO`
408		-	`lda #%00000011 ; Length counter load, high bits`
	669	+	`lda #%00000011`
409	670		`sta APU_PULSE1_HI`
410	671		`rts`
411	672
412		-	`; -----------------------------------------------------------------------------`
413		-	`; Win Condition Check`
414		-	`; -----------------------------------------------------------------------------`
415		-	`check_win_condition:`
416		-	`lda items_collected`
417		-	`cmp #NUM_ITEMS ; Have we collected all items?`
418		-	`bne @not_yet`
419		-	`lda level_complete ; Already triggered?`
420		-	`bne @not_yet`
421		-	`lda #1`
422		-	`sta level_complete`
423		-	`jsr play_victory_sound`
424		-	`@not_yet:`
425		-	`rts`
	673	+	`; =============================================================================`
	674	+	`; Sprite Updates`
	675	+	`; =============================================================================`
426	676
427	677		`update_all_sprites:`
428	678		`jsr update_player_sprite`
			...
432	682		`rts`
433	683
434	684		`update_player_sprite:`
435		-	`lda game_over`
436		-	`beq @alive`
437		-	`lda #$FF`
438		-	`sta oam_buffer+0`
439		-	`rts`
	685	+	`lda game_state`
	686	+	`cmp #STATE_PLAYING`
	687	+	`bne @hide`
440	688
441		-	`@alive:`
442	689		`lda invuln_timer`
443	690		`beq @show`
444	691		`and #%00000100`
445	692		`beq @show`
	693	+
	694	+	`@hide:`
446	695		`lda #$FF`
447	696		`sta oam_buffer+0`
448	697		`rts`
			...
481	730
482	731		`update_item_sprites:`
483	732		`ldx #0`
484		-	`ldy #20 ; OAM offset after enemies`
	733	+	`ldy #20`
485	734		`@loop:`
486	735		`lda item_active, x`
487	736		`beq @hide_item`
			...
492	741		`lda #SPRITE_ITEM`
493	742		`sta oam_buffer, y`
494	743		`iny`
495		-	`lda #%00000010 ; Palette 2 (green)`
	744	+	`lda #%00000010`
496	745		`sta oam_buffer, y`
497	746		`iny`
498	747		`lda item_x, x`
			...
515	764		`rts`
516	765
517	766		`update_lives_display:`
518		-	`ldy #36 ; OAM offset for lives`
	767	+	`ldy #36`
519	768		`ldx lives`
520	769		`beq @hide_all`
521	770
			...
567	816		`@hide_rest:`
568	817		`@hide_all:`
569	818		`rts`
	819	+
	820	+	`; =============================================================================`
	821	+	`; Enemy Movement`
	822	+	`; =============================================================================`
570	823
571	824		`move_enemies:`
572	825		`ldx #0`
			...
617	870		`cpx #NUM_ENEMIES`
618	871		`bne @enemy_loop`
619	872		`rts`
	873	+
	874	+	`; =============================================================================`
	875	+	`; PPU Setup`
	876	+	`; =============================================================================`
620	877
621	878		`load_palette:`
622	879		`bit PPUSTATUS`
			...
754	1011		`dex`
755	1012		`bne @attr_bottom`
756	1013		`rts`
	1014	+
	1015	+	`; =============================================================================`
	1016	+	`; Input`
	1017	+	`; =============================================================================`
757	1018
758	1019		`read_controller:`
759	1020		`lda #1`
			...
811	1072		`sta player_x`
812	1073		`@done:`
813	1074		`rts`
	1075	+
	1076	+	`; =============================================================================`
	1077	+	`; NMI Handler`
	1078	+	`; =============================================================================`
814	1079
815	1080		`nmi:`
816	1081		`pha`
			...
835	1100
836	1101		`irq:`
837	1102		`rti`
	1103	+
	1104	+	`; =============================================================================`
	1105	+	`; Data`
	1106	+	`; =============================================================================`
838	1107
839	1108		`palette_data:`
840	1109		`.byte BG_COLOUR, $11, $21, $31`
			...
852	1121		`.word irq`
853	1122
854	1123		`.segment "CHARS"`
	1124	+	`; Tile 0: Empty`
855	1125		`.byte $00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00`
	1126	+	`; Tile 1: Border`
856	1127		`.byte %11111111,%10000001,%10000001,%11111111,%11111111,%00010001,%00010001,%11111111`
857	1128		`.byte %00000000,%01111110,%01111110,%00000000,%00000000,%11101110,%11101110,%00000000`
	1129	+	`; Tile 2: Floor`
858	1130		`.byte %00000000,%00000000,%00000000,%00000000,%00000000,%00000000,%00000000,%10000001`
859	1131		`.byte %00000000,%00000000,%00000000,%00000000,%00000000,%00000000,%00000000,%00000000`
	1132	+	`; Tile 3: Corner TL`
860	1133		`.byte %11111111,%11000000,%10100000,%10010000,%10001000,%10000100,%10000010,%10000001`
861	1134		`.byte %00000000,%00111111,%01011111,%01101111,%01110111,%01111011,%01111101,%01111110`
	1135	+	`; Tile 4: Corner TR`
862	1136		`.byte %11111111,%00000011,%00000101,%00001001,%00010001,%00100001,%01000001,%10000001`
863	1137		`.byte %00000000,%11111100,%11111010,%11110110,%11101110,%11011110,%10111110,%01111110`
	1138	+	`; Tile 5: Corner BL`
864	1139		`.byte %10000001,%10000010,%10000100,%10001000,%10010000,%10100000,%11000000,%11111111`
865	1140		`.byte %01111110,%01111101,%01111011,%01110111,%01101111,%01011111,%00111111,%00000000`
	1141	+	`; Tile 6: Corner BR`
866	1142		`.byte %10000001,%01000001,%00100001,%00010001,%00001001,%00000101,%00000011,%11111111`
867	1143		`.byte %01111110,%10111110,%11011110,%11101110,%11110110,%11111010,%11111100,%00000000`
	1144	+	`; Tile 7: Player (sprite)`
868	1145		`.byte %00011000,%00011000,%00111100,%01111110,%11111111,%10111101,%00100100,%00100100`
869	1146		`.byte %00000000,%00011000,%00011000,%00111100,%01000010,%01000010,%00011000,%00000000`
	1147	+	`; Tile 8: Enemy (sprite)`
870	1148		`.byte %00011000,%00111100,%01111110,%11111111,%11111111,%01111110,%00111100,%00011000`
871	1149		`.byte %00000000,%00011000,%00100100,%01000010,%01000010,%00100100,%00011000,%00000000`
	1150	+	`; Tile 9: Life icon (sprite)`
872	1151		`.byte %00000000,%00100100,%01111110,%01111110,%00111100,%00011000,%00000000,%00000000`
873	1152		`.byte %00000000,%00000000,%00000000,%00100100,%00011000,%00000000,%00000000,%00000000`
874	1153		`; Tile 10: Item (data core - diamond)`