Duke Nukem: Zero Hour

Kill all opponents in level 3, "Nuclear Winter",
to unlock the cheat option for big gun mode.

Kill all opponents in level 9, "Jailbreak", to
unlock the cheat option for maximum blaster ammunition.

Rescue all babes in level 10, "Up Ship Creek", to
unlock the cheat option for maximum shotgun ammunition.

Rescue all babes in level 11, "Ft. Roswell",
to unlock the cheat option for maximum rifle ammunition.

Kill all opponents in level 16, "Hydrogen Bomb",
to unlock the cheat option for maximum gatling gun ammunition.

Kill all opponents in level 20, "The Brothers Nukem",
to unlock the cheat option for maximum freezer ammunition.

Rescue all babes in level 21, "Alien Mothership",
to unlock the cheat option for maximum gamma ammunition.


To get this game:
http://www.gamecave.com/default.asp?source=uddm&sku=021N64DNZEROHR
(Information from Cheat Machine)