So... since way too many people complained that the game was too hard, I decided to make some changes.
Changelog:
-Added controller support
-Added Better Cheats, including immortality
-Made bullets a bit faster (Speed went from 15 to 25)
-Decreased a bit the shooting delay (less time between shooting two bullets). Pistol delay went from 60 frames to 30 frames. Rifle delay went from 90 frames to 60 frames.
-Nerfed Rustwall by removing a couple of zombies
-Annoying zombie instantly spotting you in the first residential building nerfed (it was placed like this on purpose, I'm sorry for my sadism)
-Added a couple of tutorial lines
-Fixed a couple of bugs 


Here's the links:
Win: GoFile - WorkUpload - MEGA
Mac: GoFile - WorkUpload - MEGA