Start the game with PRINCE YIPPEEYAHOO to start the game in cheat mode.
Now you have:
[+] add time
[-] sub time
[K] kill all enemies on screen
[R] return from dead
[F1] show position (press again to disable)
[F3] player on/off
[F6] ruler
[Shift][T] add energy
[Shift][K] sub energy
[Shift][R] show room number and jump right
[Shift][W] show room number and jump left
[Shift][I] turn screen upside down, press again to restore
[Shift][B] show prince only, press again to restore
[Alt][N] skip to next level
[Alt][D] create DUMP?.TXT