This is a very good entry and overall shows a lot of attention to detail! The checkpoint system is handled very well, and the way you integrated a seamless loop back to the beginning is super cool! I see some mentioning it's too difficult, mostly that last jump, but idk that jump was probably my favorite part since I'm a sucker for skill-based difficulty. Perhaps if you wanted to take the project further you could have an easy, medium, and hard difficulty map.
A few suggestions and bug reports if I may: there needs to be a checkpoint the moment you loop back to the start, as I was able to pass the starting line again, die, then be taken to the last checkpoint and finish the last leg of the loop for a time of 15 seconds.
I also recommend a manual reset to last checkpoint button. While I was unable to get myself softlocked when intentionally trying to do so, I believe it may be possible in the right circumstances, a manual reset button would guarantee this isn't possible.
I spent more time discussing minor flaws than the many more great parts of this game because I see a lot of potential in it and really would love to see you refine this project into something even greater! But let me be clear, this is an absolutely amazing entry, easily in my top 10 of the jam!