Start the game whit -Developers , now press F11 OR F12 to bring the console in the window bar , and type some codes Below:
GetGranadeUn - Get granade ,unlimited AMMO
AllWeaponUn - Get All Weapon's,Unlimited AMMO
Submitted by WebMaster (BIG-X)
Start maxpayne with maxpayne.exe -developer
then press F12 to bring down the console.
Type in noclip
Then go Trough doors, if not works try trowing yourself trough them....
To go normal again type noclip_off
Submitted by The12DeadKnights
This is more of a fun thing to do than a code. During game play get out a fast firing weapon (perfered) or any gun that shoots. Then shot it rapidly so that the shells are in the air while they are still in the air pause the game and select save. Then either get killed or quit the game. When you select to go back to the point where you saved the game last the shells will be floating in mid air!
Submitted by Gamefinatic76
On the parking level jump on the barrels near the entrance to the parking lot to gain access to the roof and there will be a hut and if you shoot the door open and inside you will find a vent on the floor stand on it and you will fall through and find a dead guy and some sniper ammo.
Submitted by craig pamment