Finish a level without killing any enemies.
Kill 20 or more enemies on any level.
Beat the game, save the world.
Complete a level without setting off any alarms.
Discover a hidden room.
Defeat 25 enemies with the grenade launcher.
Defeat 25 enemies with the Uzi.
Defeat 25 enemies with the bazooka.
Destroy all of the fuel in the fuel depot.
Answer 20 trivia questions correctly.
Finish any level in less than 20 seconds.
Defeat 25 enemies with Gorbachev's blowgun.
Defeat 25 enemies with the minigun.
Defeat 25 enemies with the hand gun.
Defeat 25 enemies with the assault rifle.
Defeat 25 enemies with the silencer pistol.
Defeat 25 enemies with the shotgun.
Answer 10 trivia questions correctly.
Defeat 25 enemies with Reagan's katana.
Answer 3 trivia questions correctly.
Complete a level.