Sorry, I know I haven't shared the real version (since this is just a demo), but I plan on sharing that by next week on monday the 10th. This is just a demo. I will make another. And I know there are bugs, which I will try to remove in the real version. The instructions are simple, just use the arrow keys.
Big, BIG thanks to @griffpatch for the scrolling platformer tutorial since this is only my first scrolling platformer.