Hit Detection
I shouldn't have to touch a stupid key 5+ times for it to finally get the idea that I've touched it!
Some puzzles seemed impossible because of how crappy the hit detection was.
Take into account the frustration gained by a slowly amassing lag which just makes things worse as you die from an initial lag, which also seems to make your crappy hit detection somehow even crapper.
What annoys me most is the fact that you've made the story and game play concept well enough that I actually give a rip about how much it sucks because when things work well, I really do enjoy this game.
Please work it over into the masterpiece it CAN be.