In the game type "I" and you will get a prompt. 
Type: "quick" at the prompt. Then ALT-F1 through 
F10 to do various things:
                                        
F1  - Access all spells
F2  - Get more Mana
F3  - Kill other players
F4  - Kill enemy castle (reduces them by one level)
F5  - Kill enemy balloons
F6  - Heal
F8  - Spell experience points
F9  - Free spell on/off
F10 - God mode

CARPET -level # - to skip to level number (#)

Also Shift-K kills you, Shift-C completes the level, 
and Shift-Q takes you straight back to the DOS prompt.