The quality of all the UI and loading screens is really great! having a full options menu in your first ever game is genuinely surprising and worth praising.
I unfortunately fell into the water as soon as I entered the first phase and found out there was no respawning which kind of annoyed me especially since the game is quite un-intuitive in the way the combat works. I didn't think reloading was even working at all until I realised it's on a like 2-3 second delay, where a reload animation would be but is notice-ably missing. (Even adding a temporary UI animation for it would have gone a long way)
The style of the enemies and environments was really nice, and having a single player king of the hill gamemode was fun to play around with, would be interesting to see more complex AI.
I think the enemies had way too much health, sometimes I could unload all of my ammo into an enemy and they'd just barely die from it. A headshot multiplier would be nice too to reward precision gameplay. I also think the gun should have an actual "shot" particle effect, since when I first used it I couldn't tell what was actually happening or whether I was using a shotgun or something, since it only shows the explosion effect on whatever you hit but no projectile actually moving to it.
Overall though very impressive for a first time project!