This is a "trick" level where you need to save pretty often to avoid "failing" puzzles and dying or getting stuck. It contains mandatory use of Wings of Wrath and Chaos Devices. Otherwise, it's not badly designed or even unfair, though it may be too tough on Black Plague. At some early point there's a crusher trap. It should be solvable intelligently, not by trial and error.
This is classic for a reason. Being collection, level differs, but it actually I think less than in original D2. Level design is very clean and enjoyable through, difficulty quite balanced as well, I must say MM aged like the finest whisky, can't wait to get to number 2; this was one of the best I've played so far.