ZZT v3.2 (Registered)
In City of ZZT, you can talk to the pawn shop broker and spend 20 gems to ask for advice. If you close the menu without picking an option, he is supposed to give you back your 20 gems after three ticks. Instead, he gives back 30, which is 10 gems more than that. Thus, once you have 20 gems, if you repeatedly ask him for advice, cancel out, and wait, you can quickly build up enough money for both of the bribes required to complete the game without having to find enough gems to make them.
In Dungeons of ZZT, on the infamous "Hit The Target" board, if the player successfully finishes the puzzle with the penalty gate closed and exits to the south before taking damage from a lingering star and respawning, your respawn point changes to the south edge and you can never open the penalty gate again. This prevents you from returning to the main dungeon hub and completing the game.
(Report entered by Dr. Dos, original report by Zinfandel)
