I have noticed a few things that Perfidus seems to have that could be unintentional, and effect the aesthetics.
I'll gather screen shots of them. here's a list.
1. doorways on the stair wells seem to put you inside the door instead of outside it, and facing the wrong direction.
See image below. I didn't get the shot of Donnie facing the wrong direction, as I had to fight, however, I did mark on the mini map the two locations that plop you down behind the area transition door (inside the doorway) and facing backwards.
2. Epic, massive, demon and devil slaughter at the entry way to the temple:
Is this intentional? When arriving to the temple, there is always a spawn attacking itself in a huddle. Pit fiends, Balors, those snake women things, aberrations - you name it, and they are engaged in all out war. I find this disconnecting to the situation at hand. It would be nicer if they didn't focus on each other, and were instead of being in a tightly knit group huddled in the hallway, roaming about, spread out, inciting real fear in the hapless adventurers that wonder in.
3. There's some floating molds someplace, meant for the ground but instead they hoover about eye level. I am sure this is a mistake with the Z axis. I'll get some screen shots of those next time I run through.