I ran into some of the same challenges as the other reviewers re: weird spider spawns killing me, clipping through walls, unexpected spider collisions, and the occasional clip through a maze wall.
I'd definitely recommend adding some sort of 3D sound to the spiders so that the player knows they're nearby. Scared the heck out of me a couple times.
I thought the gun wasn't working at first because there's no feedback except that a spider died roughly directly in front of me. Even if there's no muzzle flash, either just seeing the projectile or having a pew pew would have been very helpful.
I'm not quite sure how I'd have solved for spawning spiders near the player but not in walls, but that seemed to be a common issue.
Overall though, nice job. Building out the maze and a shooter with enemies tracking you isn't easy!