Nice game! Very impressive for a first(?) game!
I do like the controls and the shooting in general. It’s very satisfying to shoot any of the zombies. The weapons seemed pretty nice, though it seemed to me like the shotgun didn’t do enough damage at close range (seems like it did as much damage as the SMG except with a slower rate of fire).
It seemed like there was a bug where I ran out of ammo for the SMG and then switched to the shotgun, but it wouldn’t let me fire the shotgun any more.
Also, I felt like the other zombies (red, yellow) should have done something more than just crawl at you like the green ones.
You should add some diagonal movement as well… it was annoying being only able to move forwards, backwards, left and right.
A BIG THING: I noticed your sounds are all from Half-Life 2. Either make sure you MENTION this in the game and in this post, or stop using them and make your own sounds. Otherwise using them is plagiarism and could get you in some trouble.
Overall very nice! Still needs some work but good so far.