Act III, after rotating those two big wheels and the first combat encounter with the "Bear" crater creature.
Note how the wheel is not properly connected to the rod:
https://i.imgur.com/r8Keuug.jpg

Executed this "Bear" (anyone wondering, apparently that's what Ebb refers to them internally) and ripped his head off with the Jackhammer. When I later looped back around to the spot the head was suddenly hovering above ground, as pictured:
https://i.imgur.com/AeR6sgQ.jpg

Another one:
https://i.imgur.com/zkvk54s.jpg

In a world where literally everything is rounded and curved I couldn't help but notice these sharp angular shapes there.
Looks like this section accidentally wasn't closed off properly or covered by other geometry/assets?
https://i.imgur.com/azqzI7R.jpg

It's a little further from the vertical shaft where you bring/move up one of the "transport spheres" via the conveyor in Act III.

Did you change your FOV at all, maybe use a fly though wall cheat? I say that because the engine will glitch and not render if you fly or wall port. Myself I noticed when I messed with the FOV it screwed up my distance rendering and I got strange geometric shapes floating the mist.

I cranked up the FOV a little, yes, but the things I've reported on thus far actually do seem related to oversight on the level designers'/environmental artists' part.

Like this one here:

The, again, angular pitch-black shape inside the exhaust-/vent-like wall element there makes me think it's missing another (decorative) element or asset (like one of the pictured variants of that same exhaust-/vent-like wall element) properly concealing it/closing it off?
https://i.imgur.com/UYEzqe5.jpg

It's located in Act IV, right across the "back end" entry point, the furthest away from the "Mother" creature's head.
https://i.imgur.com/ajugD1r.jpg

You're not supposed to have another one of those cylindrical containers (with the red substance in it) in your inventory here, I think?
You're collecting a single one from one of the operating tables just before plugging it into the terminal in the next room to move the gate and open the way and yet, as pictured, still have it on you after that, so this surely must be a bug?
https://i.imgur.com/XO6kIcr.jpg
https://i.imgur.com/VgVtbtw.jpg


Another minor visual thing in Act V that caught my eye nonetheless.
Maybe related to an increased FOV, or maybe not? Looks to me as if those intersecting angular shapes could be the result of two or more of these fog/mist layers overlapping in an unfortunate manner?
https://i.imgur.com/kPpQguv.jpg


The rather hard and abrupt transition from misty blueish-green to black on this alcoven's ceiling (in the "Krang" boss room) makes me think it's supposed to be a lot more gradual and smoother instead?
https://i.imgur.com/Zibh5I8.jpg

Another noteworthy visual/graphical glitch I came across, in the area right after arriving and getting off the rail transport in Act V.
Maybe a little hard to make out due to the image processing and compression but note the down below area to the left of the screen changing in lighting, depending on the angle/from what camera position it's looked at and then rendered.
https://imgur.com/sGGM6tQ


Corpses (like the ones of these two crater creatures in Act IV here) sometimes spazz out in quite spectular fashion, with their heads or other body parts clipping through the floor/ceiling, for instance:
https://imgur.com/F0v6HT6
https://imgur.com/IquUVNi

Still persists, by the way, even after the first "refillment" (which was just wonderfully gnarly and made me think of Rabban Harkonnen and his little juicer box in David Lynch's Dune) and subsequent emptying of the cylinder.
Plugged into the terminal/"juicer" AND, at the same time, shows up in your inventory:
https://i.imgur.com/p2DFGX8.jpg

Obviously, once more a minor VERY subjective gripe but the pitch-black circular "ceilings" inside the three alcovens of the area with the single Homunculus that opens up after lobbing a grenade inside the nearby shaft yet again look like they're missing something (like a decorative element or asset) to cover/close them up:
https://i.imgur.com/Ysh2hWE.jpg

The same circular pitch-black "ceiling" inside the third alcoven not occupied by the ammunition or healing dispenser in the other similar area that previously had two Homunculi at least doesn't have this hard, "sharp-edged" transition into the pitch-black but a somewhat more gradual and smooth one instead, making it look less "out-of-place", so to speak:
https://i.imgur.com/hqHpAyD.jpg


The alcoven on the left of the area with the singular Homunculus also is not closed off properly in a few spots and along the seams, with the out-of-bounds void peeking through:
https://i.imgur.com/EmCcaqT.jpg

All the alcovens in both areas also have these very faint, very thin cracks in the geometry/marked places:
https://i.imgur.com/9Gh170A.jpg

Three more noteworthy things right before the finale:

This angular black shape against the wall and literally sticking out from the rest of the darkness below:
https://i.imgur.com/Kb6ulS5.jpg

Another visual/graphical glitch (similar to the one reported previously) depending on the angle/from what camera position it's looked at and then rendered:
https://imgur.com/ZFJUU2C

The angular shape at the bottom(?) of this pit that's supposed to be or at least make the impression to be bottomless, as well as the diagonal "god ray"(?) right above it:
https://i.imgur.com/5WHf0NM.jpg

I've played though twice now, and I even looked for some of this. It's not happening for me. I didn't change anything other them maxing out all settings possible in menu. I'm also using the new 522.25 driver. it's looking like its due to the changes you made to fov, test it by reverting them and seeing if you see them again, also its worth playing again anyways. stay after the credits on round #2 :)