Rate my room

What kind of map designing maniac uses a different texture for the inside of the door way? Absolute mad lad.

I think it's... Missing something

Ok.
Can't do anything about the ceiling; you work with what you have. However, the bare, white angled part of the ceiling would look better a different color, like a deep blue to simulate sky. Or, anything, really, to beak the monotony and feeling of being compressed. Given the carpet choice, might as well go all in and paint it with UV-reactive purple.
I hate that ceiling light with the fire of a thousand suns. Any mood lighting - even a now-overdone rope of fairy lights, or a strip of colored LEDS at wainscoting level would be better. Or any sort of decorative table/floor lamp. That glaring overhead makes me want to stab my eyes out with an icepick. Get UV LED roping, run it around the room at waist level, and really set off your new paint job.
The carpet is interesting, but the fact that it adorns the entryway makes it fantastic. The only thing I'd change is more of it! I've got a fever, and the only cure is more checkered carpet! In for a penny, in for a pound. Two different carpet colors is clashing; if you can't get more of that carpet, get rid of the blue one. The bare floor boards would be better.
Camouflaging the folding chair is an interesting idea; for as much work as it probably took, I'd have stolen a better chair.
Seriously; tear out that fan. Or, replace it with only a fan.
The Error is art. Not my style, but you do you!
The best, single, decorating advice I've ever read is: don't shove all of your furniture up against the walls, and especially not into the corners. I know you're limited by where the outlets are, but bring what furniture you have out into the room.
I mean, this isn't the direction I'd go with this space, but that's what I'd suggest working with what you have.
Kill that overhead. Please.
- As an electrician:
  I'd put some sconces on the tall wall. Something simple and tasteful. And ideally some recessed can lights in the angled ceiling, maybe with a gimbal so you can adjust the angle of the light.
  The fact that the checker pattern on the doorway doesn't continue around the rest of the trim really bugs the snot out of me. Please carry that all the way around. Ideally, do all the trim that way, since it's all the same "texture". And yeah the carpet/rug all needs to match or go, no half measures.
  100% agreed on the ceiling fixture. In that small a space, I'd take it all the way out. If you need a fan there for airflow, there are good low-profile options out there. Ideally I'd do away with it altogether, though, and see about possibly adding a mini-split if it's too uncomfortable in the summer/winter.
  If I think of anything else I'll edit. It's a fun room, I'd love to steal the idea for a game room some day. But this implementation needs a touch more work.
  E: yknow, some floor cushions and a low coffee table might be nice there by the window instead of the hobo batchelor setup. It'll make it seem taller, too.
  
  I'd put some sconces on the tall wall.
  That is a better suggestion than my rope lighting. Of course, It'd require a licensed electrician to do... looks suspiciously
  If you need a fan there for airflow, there are good low-profile options out there.
  Another excellent suggestion, but this:
  Ideally I'd do away with it altogether, though, and see about possibly adding a mini-split if it's too uncomfortable in the summer/winter.
  is the best idea. There are some really nice, attractive in-wall options that would do a better job than a ceiling fan, with more versatility.
  floor cushions and a low coffee table might be nice there by the window instead of the hobo batchelor setup
  This is the best idea of all. Full carpet, low chairs or beanbags, and a really low coffee table; this would be a completely different room!
- I disagree with your point 1 a little bit. If the goal is to make the room look airier (or not compressed) I would get rid of the texture on the ceiling, but keep it white. A ceiling with a darker color than the walls will look smaller.
  If OP wants more color, they should add some art to the wall, or paint the walls and have the ceiling match or be lighter/white.
  The rest I agree with though.

I'm terrified of finding the spot in the room where I'd fall through the world

There is too much textures, my graphics card can't handle that

That is so cool

I don't see trigger zones for the chair and the doorway. Is the other room and full-res view out of the window in memory at the same time??
- I was gonna say this floor looks like my VR floor hehe

Reminds me of my old job where we worked on a house where the media room was done up in the orange and grey placeholder textures seen on some gmod stuff.

Remember to download CSS!

Is that a bong on the table?
- On the one hand it totally looks like one
  On the other the test of that shit looks vaguely chemistry-ish as well
  So either chemistry stuff or bong cleaning station
  
  Looks like a bong, a bottle of isopropyl alcohol, two rolls of paper towels, a thermos, and a shaker bottle

You may need this

Why the fake error :(
The lighting doesn't match

NGL I'd love to have a 3d printed error to put as decoration. So nerdy and I like it

I love this, but it also reminds me of my scene girl girlfriend's Myspace profile with the zoidberg profile picture.
Please tell me it automatically plays a really loud song from a local indie band as you as you open the door?