Just for fun.

src/constants.asm

@@ -89,6 +89,10 @@ sPause::
     db " P A U S E"
     db "P A U S E "
     db " P A U S E"
+sEaster0:: db $D4, $D6, $D8, $DA, $DC
+sEaster1:: db $D5, $D7, $D9, $DB, $DD
+sEaster2:: db $DE, $E0, $D8, $DA, $DC
+sEaster3:: db $DF, $E1, $D9, $DB, $DD
 sPieceXOffsets::    ; How to draw each piece. X-offsets of the sprites.
     db 0, 8, 16, 24 ; I
     db 0, 8, 8, 16  ; Z

src/include/globals.asm

@@ -114,6 +114,8 @@ DEF TITLE_LEVEL         EQU $996C
 DEF TITLE_ROLLS         EQU $9A2F
 DEF FIELD_RNGTELL       EQU $9812
 DEF FIELD_TOP_LEFT      EQU $9800+1
+DEF EASTER_0            EQU $9885
+DEF EASTER_1            EQU $98A5
 DEF TILE_FIELD_EMPTY    EQU 4
 DEF TILE_PIECE_0        EQU 10
 DEF TILE_0              EQU 66

src/main.asm

@@ -28,6 +28,7 @@ INCLUDE "res/title_map.inc"
 SECTION "High Globals", HRAM
 hGameState:: ds 1
 hSwapAB:: ds 1
+hInitialA:: ds 1
 
 
 SECTION "Stack", WRAM0
@@ -38,6 +39,9 @@ wStackEnd::
 
 SECTION "Code Entry Point", ROM0
 Main::
+    ; Load the initial A register. For reasons.
+    ldh [hInitialA], a
+
     ; Turn off LCD during initialization.
     wait_vram
     xor a, a

src/res/tiles.inc

@@ -444,6 +444,34 @@ Tiles::
     DB $07,$00,$00,$00,$00,$00,$00,$00
     DB $07,$00,$04,$00,$06,$00,$04,$00
     DB $04,$00,$00,$00,$00,$00,$00,$00
+    DB $7C,$7C,$42,$42,$41,$41,$5D,$48
+    DB $6E,$4C,$5B,$4A,$79,$49,$00,$00
+    DB $68,$58,$58,$68,$68,$58,$48,$78
+    DB $48,$78,$48,$78,$78,$78,$00,$00
+    DB $7C,$7C,$84,$84,$04,$04,$75,$25
+    DB $ED,$65,$B5,$A5,$3D,$25,$00,$00
+    DB $2D,$35,$35,$2D,$2D,$35,$25,$3D
+    DB $24,$3C,$24,$3C,$3C,$3C,$00,$00
+    DB $3C,$3C,$42,$42,$81,$81,$BA,$18
+    DB $67,$27,$A0,$20,$EF,$2F,$00,$00
+    DB $6D,$AA,$A6,$65,$65,$A6,$18,$FF
+    DB $81,$FF,$42,$7E,$3C,$3C,$00,$00
+    DB $3F,$3F,$20,$20,$20,$20,$AE,$A6
+    DB $B5,$A5,$2E,$26,$BF,$A0,$00,$00
+    DB $B5,$AA,$AE,$B7,$B5,$AD,$A6,$BF
+    DB $20,$3F,$20,$3F,$3F,$3F,$00,$00
+    DB $1F,$1F,$90,$90,$50,$50,$DF,$5E
+    DB $42,$42,$C3,$42,$83,$82,$00,$00
+    DB $82,$83,$43,$42,$42,$C3,$42,$C3
+    DB $42,$C3,$82,$83,$03,$03,$00,$00
+    DB $01,$01,$02,$02,$04,$04,$0D,$08
+    DB $0B,$09,$0D,$09,$0F,$09,$00,$00
+    DB $0B,$0D,$0D,$0B,$0B,$0D,$08,$0F
+    DB $04,$07,$02,$03,$01,$01,$00,$00
+    DB $E0,$E0,$10,$10,$08,$08,$D5,$C5
+    DB $2D,$25,$3D,$3D,$01,$01,$00,$00
+    DB $01,$01,$3D,$3D,$2D,$35,$C5,$FD
+    DB $08,$F8,$10,$F0,$E0,$E0,$00,$00
 TilesEnd::
 
 

src/state_title.asm

@@ -38,7 +38,33 @@ SwitchToTitle::
     ld bc, TitleScreenTilemapEnd - TitleScreenTilemap
     call UnsafeMemCopy
 
+    ; Little easter egg.
+    ldh a, [hInitialA]
+    cp a, $FF
+    jr nz, :+
+    ld de, sEaster0
+    ld hl, EASTER_0
+    ld bc, 5
+    call UnsafeMemCopy
+    ld de, sEaster1
+    ld hl, EASTER_1
+    ld bc, 5
+    call UnsafeMemCopy
+    jr .oam
+
+:   cp a, $11
+    jr nz, .oam
+    ld de, sEaster2
+    ld hl, EASTER_0
+    ld bc, 5
+    call UnsafeMemCopy
+    ld de, sEaster3
+    ld hl, EASTER_1
+    ld bc, 5
+    call UnsafeMemCopy
+
     ; Clear OAM.
+.oam
     call ClearOAM
     call SetNumberSpritePositions