I don't know if you've played any of them, but I think that recent From Software games handle realism in level design very well

Hmm, I think it is even better. You just poo and pee freely in the room (all of it will just kinda float in the air), then you exit the room and open the hatch door to open space. FLUUUUUUUSH! Everything from the room is instantly sucked to the outer space with a true waterless power flush, so you save water and the rainforest back at home Earth. Oh and don't forget the dolphins, don't you dare to forget the fucking dolphins!

The only downside is when the floating spaceshit hits the windshields of high-speed space ships, but that's what the wipers are for.

It definately had that problem to some extent, it could be quite maze-like in many levels. Some of those made sense, some not so much. It's a great game though and I had so much fun with it I didn't pay too much attention to it. I'd have to go back to some of those levels and play them with this thought in mind to really know. I think it was more of a problem in Mysteries of the Sith, the expansion pack, but then I didn't like that one at all so I'm more likely to nitpick at it, and it seemed much more poorly designed in general.
Imagine that's some alien race's first contact with us though. Talk about a diplomatic incident. And I thought the Earth ship opening fire on Minbari was a bad way to say hello.

Fortunately the pee and poo probably just freeze in the space quite soon, so maybe Earth will eventually have its own beautiful rings like Saturn, which beautifully glitter in the sunlight with all the shades of yellow and brown.

I'd like level design to be pretty strongly guided by 'realism', so that you can see the logic in a level's layout relative to what the level is supposed to be. And to my satisfaction at least Unreal succeeded in doing that. Definitely among the top 3 FPSs I've ever played.
In fact, come to think of it, it's only with the really old FPSs and TPSs that I can recall the nonsensical layouts being noticeable and mildly off-putting to various degrees, e.g. Doom II and Tomb Raider 2. Which is why Duke Nukem 3D seemed impossibly cool the first time I played it - it looked somewhat like actual real world locations! : movie theater with theater seats, restrooms, a drink counter and more. It blew my little mind back then, even though from a practical standpoint the design is still pretty unrealistic for a realworld location.

Usually the problem for me is that the level is designed pretty realistically, but is painfully linear to complete. That is, I see places I want to explore, but invisible walls or whatever else block the way. STALKER's final sequence at the sarcophagus comes to mind.

Incidentally, I wouldn't mind for a game (thinking sci-fi infiltration type game) that aims to go all out with the realism in its design, with a game element introduced in the form of being able to decipher from a map where you are supposed to go. I think there is real potential in that idea and as far as I know it's never been done.

Not sure that this is a good idea. In zero gravity you would have to balance the output of pee and poo, otherwise the recoil would make you rotate like a firework spinner.

Makes sense that UNREAL has UNREAListic level design!

That discussion is ages old... gameplay vs. "realism" (or suspension of disbelief).

I personally don't care that much - I can cherish both perfectly balanced, but "unrealistic" levels and very natural looking environments that maybe aren't that superb gameplay-wise, but draw you in with their sense of place.

So back in the day when Quake vs. DN3D was a thing, I preferred Quake (for the soundscape and gothic atmosphere and the perfect playability, but I immensely enjoyed The Duke too (in single player, for MP Quake was vastly superior).

Just like I can enjoy full 3D exploration but also the "step-dance" of grid-based movement in RPGs.

Hold on to something.

TBH, unless one is doing a mass shooter simulator inside of an actual building, the levels should be designed around fun rather than realism.

IIRC, there was at least one Doom level based upon Columbine, and I don't think that it was just the one that was used as a simulator.

You must mean a mod, right? Or maybe I'm just misunderstanding you. Doom predates Columbine by a number of years. In fact, many people believed that Doom was the cause of Columbine. (and just in case someone gets the wrong idea here, IM not saying that. Some other people were at the time)

Not really a mod, a map, but similar idea. It definitely wasn't official and it definitely wouldn't have happened prior to the particular shootings as iD has never been located anywhere near Colorado at any stage in its development as a company.

Modern Prince of Persia series comes to my mind. It seems the entire world are built to suit the Prince's parkour ability as opposed to living castle.

Oh, very true. It's been a while since I played those, but that is a perfect example. Great games, tons of fun, but yeah, unless you're a parkour master AND can manipulate time, there's no way you could even open the fridge.