-The zip file needs to include the .exe and the .pck file, not the godot project.
i am preeeetty sure you needed your walls to be rigidbodys with collisions. Maybe it was my copy but, i was clipping through everything.
On your player controller, move your head spatial node up, and the camera down to the same level. That fixes the bug where the camera moves up and down when you look around.
Anyway, good job.