I think it's a very original game, to be honest! I appreciate that you added the difficulty tab so we could adjust the difficulty, that said, I think what was most difficult to me was that I had to move the mouse to get air and energy.
I don't know if other people found that iffy, but I just didn't like it since I have to look away from the enemies, and check where my mouse is at instead of just blindly pressing a key, yk? So yeah, I think that was the main drawback for me in terms on gameplay. Other than that the visuals are simple but work and the audio is pretty nice as well, though I would made add a greater warning for when your air is running out, maybe? cause I wasn't really following, and I lost my air a couple times :(( could be just a skill issue but yk.