Dungeon is an indoor level, it is the dungeon for the Return to Dark Castle Teaser. There are a few bugs in this level such as invisible bats at times.
A few interesting things about this level, is that, even though it is named after the Dungeon level from Beyond Dark Castle, even though it is more like Trouble 3 from Dark Castle. Though there are some notable changes, such as the gate, and 2 switches. One of which opens the gate, the other of which opens the gate.