This is a work-in-progress platform engine. I called it a platform playground because I play around with ideas to get the script to work. Arrow keys to move, and don't touch red. If you get stuck, press r to restart. There is double jumping (hold the up arrow after a single jump) and touching black should recharge your jumping energy, giving you the capability to double jump. There is also a wall climb feature that is an accident. Hold the left or right key while against a wall, then hold the up key as well. You cannot jump after wall climbing. I will try to work with this wall climb capability, but if it becomes annoying, then I will try to eliminate it.
Thanks to all of the platform engines that showed me the magic (and difficulty) of velocity scripts and collision sensing. I have better engines now: https://scratch.mit.edu/projects/70559862/ and https://scratch.mit.edu/projects/94409951/