It starts off slow. It starts off very, very slow. But when it ramps up, holy shit does it ramp up.
I can see what they were going for, really. It presents itself like a standard dungeon crawler with your standard type of map. Then they introduce the wall breaking as if to tell you "this is not the shit you're used to", and you can just plow through that generic floor layout like it's nothing and turn the entire genre on its ass. Then later maps start getting designed with this mechanic in mind so you can't just bulldoze your way across it while bringing in all sorts of other shit and it kinda stabilizes until the last few areas where the story goes absolutely goddamn bonkers and pulls all sorts of crap on you that no reviewer would have ever let slide without raising all hell, and the only reason you don't hear about it is it's so late into the game they never got there.