This was fun. I am not sure if its a bug but if you smash space in a panic your little dude can like grab and jump even with his forehead haha. Super cool idea with slowing down and speeding up.
I liked what you did with the ever changing levels that was neat and kept it interesting, I did find the red box moved left and right very fast. My critique would be to not have it go on forever and maybe add a timer to give you more intensive to collect more coins.