Thanks for getting back to me! I'd be more than happy to elaborate on some of the things I mentioned. There isn't a crosshair in the windows build of the game, and when I shoot, it seems to land towards the right instead of the center. The bullet trail is helpful though. There's also no indication that an enemy has been hit, they don't change color (that I noticed) or make a sound effect. A sound effect might be more helpful than the color change since most of this game is in darker areas. I found that collecting ammo was also pretty unclear, I didn't know you had to step on it at first and kept trying to interact with it.
As for the textures, there's quite a bit more that I noticed than just Z fighting (that weird flickering/clipping). The gun is partially transparent; it looks like its normals are flipped or the wrong faces are being culled. Same goes for a lot of the roots/branches in the second area. Not all of the textures are oriented the same way, sometimes the bricks start going vertically. There's also a few areas where the walls seem like they have stripes running up and down them, though this might be more the UVs than the textures. The UVs do seem off in some places where the texture starts warping (ex. floor of the swimming pool area). Most of the textures on the walls are pretty low res, but they're used on such big objects that the jpeg artifacts are visible. This is a fairly easy fix though, just tile the texture of the wall materials a bit. If anything I mentioned here isn't clear, you can always reach out to me on discord (kazamis) and I can send you screenshots of what I mean. This is still pretty impressive for a first time 3D modeling, you made quite a bit in such a short time! I'm glad to hear you're continuing on this project and I wish you the best of luck!