Press 'SPACE' on the title screen and select password from the menu. Now enter one of these for the password:
"REANIMATOR" - for level 2
"PSYCHONAUT" - for level 3
During play type any of the following:
"I NEED OXYGENN"------------For full oxygen
"I NEED ENERGY"-------------For full energy
"I NEED A MIRACLE"--For infinite everything
"I NEED A MEGA BLAST"------For a smart bomb
Type any of the following for various messages:
"JOHAN LINDAHH"--- | "J.LINDAHH" | "HUNTERR" | "I LIKE ATARI"
"I LIKE FAIRLIGHT" | "I LIKE DM" | "SAUROO"- | "JENN"