HATMAN: turns Jim into a stick figure.
IDDQD: shows EWJ team and prints "Nice try! This isn't Doom".
IDKFA: shows a group photo of the EWJ beta testers.
ITSAWONDERFUL: gives Jim an extra life.
ONANDONANDON: gives player the maximum number of continues.
POPQUIZHOTSHOT: maxes out normal gun with 1,000 shots.
SLAUGHTERHOUSE: allows player to jump to any of the first five levels.