Jazz Jackrabbit

Pause the game by pressing P. Then hit backspace, and type any of the following codes.

BOUF (temporary invincibility)

GUNHED (gives you all weapons)

CHECK (displays some numbers on the screen)

GREETZ (opens an "Arjam Greetz" window)

DOOM (flashes the screen red)

LAMER (jump to next level)

APOGEE (slow, 16-color mode)

SABLE (super sonic speed)

CSTRIKE (gives you the air-board)

HOOKER (takes you to bonus stage when current level is done)

BAD (gives you the bird)

HOCUS (teleports, provided you have an enemy above or below you)

ARJAN (HAHAHA displayed on screen)

TIM (displays A WESOME on screen)

MARK (lose a life and start over)

KEN (?)