This is really awesome, it has a good amount of content. The music is also really nice, it fits the game nicely. The fog helps set the creepy atmosphere as well.
The first thing I want to talk about is the enemies. The pathfinding is really good, they usually know where to go. I like the fact that if they can't see you, they go into a sort of calmer idle/waiting for you to show up state. One thing I thought was a little annoying is that they go for the player straight away, so you get hurt right as you respawn a lot. This is especially the case with the wizard/mage enemies. They shoot at you the second you spawn in, so you have to be really quick to dodge the attack. The enemies can also corner you really easily, which will almost always lead to your death. This leads me to my next point, the weapons.
Going back to enemies cornering you, once you're cornered, you cannot kill the enemies. The guns shoot bullets from the very tip, so if an enemy is right up against you, you will not be able to hit it anymore. The pistol does an extremely little amount of damage, which is kind of understandable as it doesn't use any ammo, but I think you should raise the amount of damage it does by at least a little bit. I really like the different weapons, I think you should tell the player how much ammo each weapon uses. I did encounter some bugs with the combat. 1) Occasionally, all projectiles fired will just stay frozen in midair. It does that with both projectiles fired by you or by the mages. Enemies still get hurt by the frozen bullets, and you can stack them to deal a lot of damage. I noticed it after 20-30 rounds, it might've happened earlier. They usually just stay like that for the rest of the round at least, sometimes they suddenly unfreeze and keep going in their original path. 2) I only encountered this once, but when I picked up the pistol, it was inside the player and refused to shoot. I was down to 1 ammo, so I couldn't really do anything else at that point.
The world generation is really good, but sometimes you get surrounded by trees and shrubs and have to shoot your way through to get to the enemies. Occasionally, I had a bit of trouble finding the exit because it was hidden behind walls of trees, sometimes quite a bit away from the center, so I had to do a bit of digging to find it.
One thing that isn't really necessary but that would be a nice touch is to give the player some sort of motive or reward for playing. Right now, you just keep going until you decide to quit, you don't really get anything for playing. Maybe giving the player some sort of reward or something they can unlock by reaching a certain amount of rounds will keep the players playing and make the game more interesting.
Other than this, it's a really cool game. The endless levels and different weapons make it really fun to play, and I like the unsettling atmosphere. It could use a few more sound effects, particles, little things to make it feel more polished, but overall it's very good. Keep it up!