Hey mister developper, I think I found a flaw in this game, other people try this to confirm it please : If you finish a level, but instead of pressing the "next level" button, you press the "return to menu" button, the next level is NOT unlocked in the level selection screen, even if you beat the previous level.
thumb up for it to get repaired, so nobody has to do the same level twice(unless they want to)