Left and right arrow keys to move. This is a small slope detection engine I made. It's by no means perfect (mainly due to the limitations of scratch), and does require running in turbo mode to work properly (hold Shift and left click the green flag). It's also EXTREMELY laggy online.
Please don't ask me to explain how this works. See inside if you're wondering. But if anyone wants to improve on this and maybe make it run well without turbo mode, I have absolutely no objection.