WAAAaaaayyyyy more interesting than its direct predecessor, with much higher highs. Structurally, conceptually, visually, as well as narratively, this game hits the mark. Sadly, however, its lows are astoundingly low, and its second half being a pretty crappy escort mission through areas you already explored hits the game in a way it never fully recovers. For as great as the room sections were, the dungeon crawling moments showcased tons of questionable design decisions, to the point I can't, in full consciousness, call the first half fantastic either.
It's a flawed game; flawed up the whazoo, but even if not originally intended as part of the series, it's such a unique beast that I cannot imagine myself preferring the series without it.