In the Japanese version, entering "おわひ" (Apology in Japanese) will reveal the hidden message "ぱすわーどがながくてすみません" (Sorry the Password is so long), presumably a message from the developers, apologising for the game's up to 104 character long passwords.

The "Disco Sucks!" poster in the PC version of the game is still present in the NES version's ROM. It was most likely cut due to Nintendo's censorship rules.

In the NES version of the game, despite heavy censorship, the scene where the player can put a hamster into a microwave oven was left in the game. Nintendo discovered this just as the first run was being shipped to retail, and stipulated that no more copies could be manufactured until that scene was censored.

In later versions of the game, including the PAL version, attempting to put the hamster in the microwave will only cause the game to respond "HOW SICK!"