I MADE A PLATFORMER! Use arrow keys or wasd to move, there's really nothing else to it. Red will kill you, blue makes you bounce high, and yellow makes you progress in the level.
I have to give thanks to the user @TeachUDude https://scratch.mit.edu/users/TeachUDude/ for his platformer tutorial. Also, constructive criticism is accepted, as it helps with me improving in my coding skills.