A Trap Door appears once you trip its switch, and acts like a locked door. One use of a Trap Door is to trap you, rendering the level impossible. Often, the switches are concealed behind objects, usually gold, where you may not see them until it's too late. This is seen in 02-4: (Don't) go for the gold.
- 02-4: (Don't) go for the gold)
There are a few cases where the Trap Door is actually required to complete the level. For example, 51-2: It's a trap! locks up the seeker drone, allowing you to complete the level, and 82-0: Leap of Faith by Castaway creates a staircase of Trap Doors for you to complete the otherwise impossible level.
- 51-2: It's a trap!