Hi Kodub,
Just wanted to say that this is a great game that you've created. Runs so smoothly, all in a browser too!
My suggestion is to calculate a global rank for every profile. I feel like if you logged in to the game and the first thing you see is your global rank and your percentile(global rank/total ranks * 100), it would be really cool. Seeing your global rank improve every time you get a new PR would definetly increase motivation. It's like the leaderboards that you show for each track, except that this leaderboard would be for ALL tracks. You could separate this leaderboard into Official Tracks and Community Tracks too. I think the global rank itself could be calculated by getting the average of all your ranks on every track, or something similar.
Thanks!