Really nice Concept, managed to get to, what seems to be the end. maybe you could add a Victory Screen on the final flag. wasnt sure if there is more :)
also if found a minor bug: after the 6th checkpoint, behind the big lava pile where it goes down like stairs. if you touch the dirt that is spaced 2 blocks it kills you like the lava.
Also what is your speed record in this game ?
I did it in 1:08