Some rooms are specially marked with a purple question mark, and have unusual contents. I've found some minibosses, some bonuses, and some that don't have much gameplay effect. What all different types of special rooms are there, and what are their effects?
Not 100% that this is the entire full list, but I've seen:
- Booyan the Clown: Challenges you to use either five axes or ten daggers to destroy a bunch of targets, gives a prize of a large chest if you do well, or else at least gold for every target hit.
- Shrine: Pray at it to receive an item.
- Paintings: Give details about previous games by the same developers. Sometimes, they turn out to be a Doomvas variant, and killing them creates a chest.
- New Spell: Swap out your current spell for the new one sitting on a pedestal.
- Jukebox: Lets you play any song in the game, but only while in that room.
- Fountain: Restores a chunk of HP and MP.
- Gambling Elf: You can pay him 25% of the money you have, in order to open one of the three chests behind him. Two are empty, one contains 3x what you paid.
- Diary rooms: Read the diary to unlock another entry and learn a little bit more about what's going on.
- Red teleporters: Teleport you to a random room. Changes each time you use it.
- Miniboss: Kill a miniboss (sometimes one enemy, sometimes a pair of them), and they drop a large chest.