Cool game! Took me a minute to figure out what the arrow keys did, but after that I had a fun time. Good job.
My only real criticism is that there doesn't seem to be a way to gain back ground after you lose it, or jump perfectly so that you don't lose ground. Or maybe I just couldn't get the rhythm right to not lose ground sometimes.
It also looks like you've uploaded a web build, but you haven't enabled it to run in browser. You need to click "This file will be played in the browser" in your project settings for that file.