-Orc cryomancers. Oh so very very much.
-The maze.
-Having to do the six orbs puzzle over and over again with each character.
-Hybrid classes. What kinds of stats is a Wyrmic or Arcane Blade supposed to put points in?
-Grinding because you've run out of safe-ish dungeons but won't dare enter Dreadfell until level 27 -- And even that's a bit risky.
-Being permanently confused because you're standing nest to a headless horror you can't get away from because you're confused.
-SKELETON. MASTER. ARCHERS.
-Reknor. The levels are too large to find anything, and are full of multicoloured dragons.
-Spending half an hour searching for the exit on a level and finding that it's about five squares away from the exit.
-When the minotaur fails to drop his awesome magic mapping gem. I forget what it's called but it's the best light I've ever found.
-When you're told that the staff of absorption got stolen even though you killed all the ambush.
-Having more than seven abilities.
-Enemies getting WTFHAX critical hits at the worst possible moments.
-When the game runs at 4 FPS because there's an acid cloud on the level.
-When the game runs at 4 FPS anyway.
-Being sandwiched between some gravity-altering abomination and the Sandworm Queen in an unstable tunnel.
-The tidal pulse attack that orc high cryomancers have.
-The Shimmering Caves. My anorithil had difficulty there at level 15.