At the entrance to the desert area of the game a cobra demands jewels. If Rook attempts to Give all of his gems to this snake, it will halt execution with a programming error. It attempts to jump to a label named :Go, but #Go is a reserved word in ZZT for movement, and so the engine errors out on a #Go statement with no direction. The only way past the snake without ?zapping is to attempt to pay him all your gems while carrying no gems at all.
In the throne room, the Captain fails to zap his :touch label after Rook tells him what the prisoner said, and because of this, the initial check for the flag Torture and initial message will always execute, the check to see if you have the Garlic will never execute, and the Captain will never move away from the passage you have to enter.
In the underground vault, the object, which is supposed to open the vault, again attempts to jump to a label named :Go, and thus triggers ERR: Bad direction and halts execution, requiring Rook to zap the vault door out of the way himself.
Lastly, the final board of the game contains a hidden anti-editing/anti-ZZT rant. This board is the corrupted last board of a Super Locked world, meaning it will crash ZZT if you load it, and thus ironically cannot be read without the use of an external editor or viewer made years after its release.
(Report entered by Dr. Dos, original report by The Green Herring based on bugs mentioned in the game's Closer Look article)
Dos sez: Game rules though, and you should still play it.
