Great. I designed it to be impossible if you don't go the correct way, it's about understanding how the alligators move, it's just an interesting puzzle.
A robot could beat all levels very quickly by smashing buttons almost instantly. The tiring of the fingers when pressing the buttons to move the frog very constantly is another factor of the difficulty.
Well, but how did you change to the standard difficulty, I think it could better has a difficulty selector in the game, & return to main menu when all levels are complete.