Commander Keen 6
F10-E - End level
F10-G - Invulnerability
F10-I - 99 ammo, all keys and items
F10-J - press and mouse and you can fly
F10-N - no clipping, but you die, if you leave the level
F10-W - Warp to any level
F10-Z - Background turns grey and all secret ways will be visible
F10-D - Records a demo, pressing F10+D again will save the demo.
Pressing b,a,and t all at the same time does the same thing as F10 and
I.