Start the game with the following command line:
For Spear of Destiny:
Start a new level or saved game, once your acually playing hold down these three keys at the same time:
You should see a message the says,
"Debbing keys are now available!"
Now you can use the following key combinations to cheat:
TAB-W = Warp to any level (1-10)
TAB-I = Free items (Bigger gun, more ammo, health)
TAB-E = Exit to next level
TAB-N = No clipping (Walk through walls)(Version 1.1 and S.O.D. only)
TAB-H = Hurt youself
Then there's the "MIL" cheat that gives you 100% health, 99 ammo, and both keys but you score gets set to zero.