Use the arrow keys to move and jump. If you jump while clinging to a wall, you can wall jump. Falling to the very bottom of the screen or touching the lava will result in a restart of the level. You need a key to open a door. Some levels may seem difficult but all levels are possible.
I used the script of how to make the ball move from this tutorial: https://scratch.mit.edu/projects/34429446/ It helped a lot, thank you very much! All other artwork, level design, and programming was done by me.