Hello, I am meburningslime, long time user of flowlab and a decent game creator. Many people come to the forums to search for answers to their problems, so I have created a simple, code-organized game to help you out on making platformer games. Here you go!
https://flowlab.io/game/play/1432739
If you want me to add anything into it, just ask! I will diligently watch for suggestions and even criticizm for the code. Have fun making your world!
–meburningslime