Yeah I'm not too happy with how level 4 turned out, if I could go back and change it I would probably introduce the buttons in another level without spikes first just to get people used to the mechanics.
Thanks for the feedback on the movement mechanics, definitely would change the amount that the player moves to be more balanced for future games or at least shift focus more towards the puzzle aspect instead of trying to go 50 50 and getting something less great than focusing more on one.