Alleyway:ROM map

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  • 0x03B5-03C0 = OAM DMA Transfer subroutine
  • 0x03C1-03FE = Joypad subroutine
  • 0x07E8-07F1 = Decrease lives
00:07E8	FA 44 CA	ld a,[$CA44]	(Put in A the value in address $CA44=Lives)
00:07EB	FE 00		cp a,$00	(Compare the value of A with $00)
00:07ED	C8		ret z		(Return if is zero)
00:07EE	3D		dec a		(Decrease a)
00:07EF	EA 44 CA	ld [$CA44],a	(Sets the value of A in the address $CA44=Lives)

If you changes the instruction in 00:07EE, you can have infinite lives.
00:07EE 00              nop             (NOp Operation)
The lives don´t decreases.
  • 0x1C42-???? = Level data
0x1C42-1D08: First levels
0x1D09-1DCD: Other levels

Notes (Bricks values):
00: Without brick
01: One brick
02: Two bricks. One in the position and other above it.
FF: End of level data