This game has potential, but unfortunately it's very unpolished at the moment. I can imagine myself playing it on the mobile device (do you have plans to make it possible?), but for now it's definitely too hard to play.
Music and sounds are interesting. I like the idea of overheating the weapon. Graphic style have some charm to it too, somehow reminds me of older 3D games.
Like others before me have said, camera controls feel weird, it's very slow and I couldn't even turn around fast enough when someone was shooting at me from the side. I also had strong impression that there's some delay.
The issue for me was also that if we press movement keys when shooting and then we stop firing a weapon, our character will stay in place. I think it would help a lot if you check if player is holding movement key right after we stop shooting.
Retry button after losing didn't work.
During the talking with NPC I was confused and I thought that the game froze, because there was no "Enter" button listed in the controls. I think that letting players proceed with the interact ("E") button too would be intuitive.
I believe that the player's weapon is too weak, I think the whole magazine wasn't enough to put down one enemy, when they could defeat us without stopping even for a moment. It would be nice if our gun was stronger, but if you don't want to do that, maybe you should at least make enemy weapons overheat too?
Enemy AI seems a little off. Sometimes they don't see us even from quite close range, while other time they can shoot as from very far away. I think that complete lack of reaction when we are shooting at them is weird too. I would consider changing it so they can see us only from closer distance. They could also react to our shots even from far away (maybe even after a few seconds), starting to shoot at us. It would encourage hiding and getting to know enemy routes, so we won't end up too close to them because it would be too risky.
General idea is fun, but it needs a lot of improvement. I believe that you will be able to repair it, I will check it out again in the future. Good luck :)