1st: it's fun to test yourself again and again and try to avoid mistakes (which will inevitably happen again and again), 2nd: is also annoying as hell.

The game does nothing wrong, it's fast, it's a challenge but it doesn't forgive even a small misstep. Anyway, I'm not going to complete all Archievements (I proabably would going to hate myself for doing this), it's really enough for me to have played through it.