Yes, you missed the invisible path. And I see you played hard :D! Behind the left crate is invisible way that you must go. In easy for some reason ground collision bugged and decided to stop working, so you or go perfectly straight, or go the invisible path. And a lil easter egg in the beginning of the hard level: there is a small yet visible path filled with spikes that leads you to invisible path, that if you go straight up, leads you right to the end.
You are right, visible timer would help. About visible indication of spikes in hard, hmmm, not too interested in doing that. It is supposed to be hard. If you beat the game click surprise button for a surprise >:)
Thanks for playing!