Wolfenstein 3D / Spear of Destiny

Start the game with either 'wolf3d -next' 
for v1.0, or 'wolf3d -goobers' for v1.1+
To activate the cheats, press either 
CTRL-TAB-ENTER for v1.0, or ALT-SHIFT-BACKSPACE 
for v1.1+ Now hold TAB and press these keys:

E - Jumps to the next level
G - God mode
I - Get items
C - Clipping toggle
W - Warp to level of your choice