TL;DR: A nice idea that kinda falls apart in the implementation.
I kept finding myself getting caught on what seem to be small invisible bits of terrain that sent me plummeting into a pit. The spider enemies sometimes bug out and stop moving (and the one spider that's most prone to doing this usually ends up sitting on top of a one-way platform you need to jump up onto from beneath, making the level near impossible to do.)
The aesthetics & cutscenes are nice, but the latter tend to drag on a bit, I think you really should've added a "skip/fast forward this" button. And you don't get any points for the former because the aforementioned aesthetics are borrowed/copied from Gyossait.
The whole "obey or don't obey" thing turns out to not matter one bit, since which ending you get is decided solely by which choice you make at the end (and whether or not you killed any enemies, but even that only changes 1 ending.)
And lastly, the mid-way checkpoint that you reload from is BEFORE a 2-minute corridor. A move that seems to exist for the sole purpose of wasting time.
And on a story note: Why can't we spare Tamas? If you leave when he begs you to you get a medal for "Sparing him", and his text changes to "You're gonna spare me?", but you can't actually do it because the elevator that takes you to him is one-way so you can't leave.