Wow, very impressive work!
Critic time (imagine 10 times that amount of the text below, praising you and this mod, please!):
I find the "you always have to reload manually" mechanism annoying. Would like "reloads automatically if you try shooting with an empty magazine but you can always reload manually" much better.
The mouse is way to inaccurate for me. Might be a Linux issue? I have no idea. It hops around the screen in what feels like 5px jumps. Might be too high sensitivity, I'll try.
The monsters tend to walk in lines.
The chainsaw did not work for me.
Does the exact mouse position actually matter or does it just decide the angle? If the ladder I would suggest making the aiming work more like in "now i forgot the name of that game, duh. That one with the electro cannon." where you can get a laser sight later to pinpoint distant shots. Basically the cursor would stay on the same radius around the player.
This might be a personal pet peeve but I like it more if a) the monsters stand out more from the background somehow and b) if dead monsters are less visible instantly.