Thanks! This is really good feedback. #1 and #3 I totally agree, noted for a future version. I like 'vigorously pressing scape', maybe that should go into the game tagline: "Vigorously press space through 12 challenging levels to recover the Time Crystal" ;)
#2 I actually quite like! (in level 12). I was deliberately aiming at using the fact that the game is 3D, despite movement being just 2D. It's designed to make the player think: "where do I have to go now?". But if it's annoying, then it's annoying... let's see if I get more feedback on that. Maybe there's a way to make it more obvious.
Yes, I agree that the end scene could be cooler. That's partly lack of time, partly lack of 3D modelling skills. ;)
One question: did you do level 10 without the slow powerups? That's some fine skill...