This feels really nice to play, the atmosphere, audio and game feel really go together. The moment when your gun runs out next to a big group is ...something
Minor flaw: Needs more enemies as you can usually just run away.
Glad you had fun! If you were finding too few enemies I highly recommend trying one of the harder difficulties. All difficulties increase the number of zombies every round so it gradually gets harder as you play, but the lower difficulties start out pretty slow for players less experienced with FPS basics while the higher difficulties ramp up pretty quickly. Or do you think it was too few across the board?