I played on linux with steam's proton just fine.
I really like your first person animations.
I fell into the void in the tutorial stage way too many time
and there were no checkpoints, which made me try to speedrun the tutorial in many places and I found out some things.
Any vertycal wall, no matter how tall can be zig-zagged up with wall running and jumping - I was able to just skip to the section with enemies you need to kill to disable the red wall. That wall also broke in one of my attempts - The blockade stayed there even after I dealt with the enemies, but I was able to wall run zizag over it too.
It was not clear in the tutorial where to go at times (the intended route) partly because you use one sided planes for your floors in many places (including your normal stages), which is not good.
At some point I realized how small the player character really is - CYBER MANLET
I just found that amusing.
The normal level was interesting, but it can be cheesed using the zigzaging i already mentioned (I got to 2 or 3rd checkpoint)
I had to end my run, because I ended up in a naughty box
As for your story, maybe it is just me, but I think it is fine to mention it takes place after world war 3 trying to prevent WW4, but no reason to mention individual countries' names.