If you’re interested, there’s this site which has lots of interesting Wolf3D things, including Wolf3D for the Mac! Included are additional custom levels and such. Visit the site now!
At any time during the game, press “ILM” at the same time. You will receive 100% health and full ammo (including the almighty chain-gun!). Caution though, as your score will be reset to zero once you use this cheat! Happy cheating!