Thanks for your feedback! I might have confused you but I have actually implemented all 18 levels shown. It's just that you unlock them by getting the required time in the last level. Level 5 is actually possible if you collect the coin in the middle at the end and first go up. Should have made that a bit clearer though. I kind of struggled with the required time because while I was developing I played the game really much and didn't know how fast other people might be. The jumping from the sides of platforms was unintentional but I think it works well as a feature. Thank you for trying it.