First of I would like to say that I appreciate the hints in the game, they really helped. But i would tone down the sound effect when a letter is being typed.
Second i found two "bugs" in the game, one is right after you kill the mutant and you are supposed to go into the bunker. Instead of going into the bunker I looked around went behind the tower and couldn't move out of there anymore, I started pressing buttons in hopes of getting out of there and then the next level loaded i think q or e where the last buttons i tried.
The other bug was inside the tunnels and is not really a bug but more so a level design issue, I took a couple of wrong turns and found a tunnel that lead me to the end of the map, where I fell through into nothing.
I wish the character was a little bit higher or the levels smaller, it feels like I'm close to the ground like I'm playing a toddler with a shotgun.
Also visual effects when you shoot something with the gun would also be nice, so that the player knows if the bullet actually hits the target.
Other than that I really liked the game, You can shoot, you have enemies and you have triggers / interactables. Well done! Please keep working on the game, would love to see more :)