25 levels full of puzzles, start very easy and slowly gets harder and harder until the level ~16 when it gets stagnant until the last four levels, not all rooms and every level is harder than previous one.
An excellent mind-broken game which follows the history from the end of the first one (King Dugan's Dungeon).
As the other reviewer, I also suggest to play Gunthro which is easier than this one or KDD.