Complete all of the operations (includingn Ambulance Mode) without making any mistakes, watch all the hard discs, and find the bobble head in Ambulance Mode. Once done, you'll unlock Random Mode, which includes a clown doctor, a dubstep song, a pistol tool, new operations, and other bonuses.
When starting the game, eject the disk labeled "Controls" by pushing the black button. Grab the "Deep Dungeons of Doom" disk located next to the computer and insert it in the drive. A game will appear on the screen; a reference to another game also developed by Bossa Studios.