The time limit to hit all of the keys seems very tight. For me, part of the problem is that when I'm using WASD to control something, I don't think of them as the letters "W, A, S, and D", but instead think of them as directions (Up, Down, Left, Right) so I'm having to mentally translate that in the short ~2 second timeframe and that's making it a bit too difficult.
The sound and visual design is SO good. I really really enjoyed that.