Press [I] to pause the game, then type RATTY at the prompt. Now you
have:
[ALT]+[F1] - Gives you all the spells
[ALT]+[F2] - Gives you more manna
[ALT]+[F3] - All magicians die
[ALT]+[F4] - All hostile castles will be destroyed
[ALT]+[F5] - Balloons will be fireballs
[ALT]+[F6] - Heals you
[ALT]+[F7] - Kills all creatures
[Shift]+[C] - Completes the level