Interesting concept to start the game at the retry screen and then play the map in reverse with reversed controls. For added difficulty, perhaps the character could move a little faster.
Further improvements: Currently when you do get hit by the razor projectile things it brings up the retry screen, however, clicking retry doesn't do anything . Or when you fall of the map, the retry doesn't bring you back to the beginning or back to the map so you'll have to manually go to menu to restart the level. Consider adding a type of check for how the player died.
Good luck with future projects!