1) To start the game type in WOLF3D -GOOBERS
2) Once in the game, Hit ALT, L-SHIFT, + BACKSPACE At the same time.
a) This enables your debugging.
3) Use your tab key & a letter. Try'em all see what they do, here are some.....

a) TAB G = God Mode ( You can not be killed )
b) TAB W = Select level ( Warp to any level you want )
c) TAB I = Free Idems ( Bullets & Big Gun )
d) TAB X = Extra Stuff
e) TAB S = Slow motion effect
f) TAB B = Change border color

Tab and some of the other letter keys will produce some different results...Experiment and see !

4) If you do not choose to use the GOOBERS cheat, and are playing in the regular mode, you may use another type of built-in cheat... ( This will also work with the debugging enabled )

Just hit the keys MLI all at the same time, and you will be given 100% health, full ammo, the largest gun available, and all the keys ! But...for all this, your score will be taken to zero, thus knocking you out of a possible high score... You can continue to use the MLI trick as many times as you like.