The hitbox makes no sense, you can jump/climb up random walls, sometimes you can only reload one bullet even if you have max ammo, and sometimes you hit the other player (blood appears) and they take no damage.
Because all of the levels look the same and the new enemies aren't different or challenging enough, it feels like playing the same level over and over again. Maybe a little more difficulty, different playing fields (maybe some stationary obstacles rather than just a blank field), or different objectives would make the game more fun?
Is it really necessary to have that "inventory full" message every time you mine over something with your inventory full? I don't care that I'm missing out on some coal, I just want to get up as fast as I can.
I loved the gimmick of the smoke/smoke rings, and the puzzles were great. But my favorite part had to be how the puzzles tied into the story (thought it was better done in this game than the Company of Myself). Awesome work.