Besides from windows and details here and there, what should I add?
(Also I’m not that good at making infrastructural builds so I’d say this build is somewhat eh)
I kind of like this, I’m getting an MM2 kind of lobby vibe. I would just say colour coordination is what you should work on. When working on builds, you can tell what colour fits with another. Just try to make the gray fit with the black a bit more, and detail is important too. But that’s all, good job.