This game rocks. Looking forward to new levels.
I don't think the levels are too hard, you only need to get used to the controls. You can fix messed up jumps by stopping shortly and continue after that. Lvl 10 was the hardest tbh until I understood the trick with jumping against second platform to get the top switch first.
Actually I would only change the Keys, because sometimes I confused jumping and stopping. So make it that they aren't near each other on the keyboard or just let them set ourselves (imho).
I didn't have problems with laggy input or "too close"-platforms, that game is all about timing, else it would be too easy.
Really awesome music by the way :)