To enable Cheat Mode, start maxpayne.exe with the command line parameter "-developer". Press F12 then while in the game snd enter the following codes:
All Weapons, Invincibility, Health, Ammo: coder
God Mode on: god
God Mode off: mortal
Add Health: c_addhealth (100)
All Weapons: GetAllWeapons
Infinite Ammo: GetInfiniteAmmo
Show Framerate: ShowFPS
Set Wounded State: SetWoundedState
Set Normal State: SetNormalState