Hey Sophie,
I really like the parkour course over all. It is an interesting concept. I haven't seen many race courses, so this would be a good addition. One thing I did notice, though, is that when soul sand comes up on the black side, I think the jump is impossible. if it isn't, it is very hard, because from what I've seen, Akane hasn't beaten it yet when I asked him to test it out. Either it is impossible, or gives the white side a very high advantage. Also, I think you should add more decoration to make it more appealing. Maybe glass panes in the middle, decorations on the edges, just to make it more appealing to the eye. But over all, I like the course, just change the soul sand an ice to glass, and I think you should be good!
Best of luck!