POKE 43575,0

This removes the command;

DEC (HL)

Which is used to decrease the player 1 life counter held at 38589.

POKE 45520,0

This removes the command;

DEC (HL)

Which is used to decrease the player 2 life counter held at 38589.

Immunity:

POKE 43848,201

This changes the command;

RET NC

To instead;

RET

Which prevents the rest of the code executing past that point to handle collision detection.

Less Animals:

POKE 44786,88

See Ending:

POKE 39393,0

Less Enemies:

POKE 39702,30

Always Walk Fast:

POKE 44675,255

POKE 44677,84

POKE 44685,186

44675	AND A
44676	RET Z
44677	DEC A
44678	LD ($96B0),A
44681	RET NZ
44682	LD (IX+$05),$47

44675	RST 56
44676	RET Z
44677	LD D,H
44678	LD ($96B0),A
44681	RET NZ
44682	LD (IX+$05),$BA