The source code for the game is over here: https://github.com/maxbize/PICO-8/tree/master/Driftmania. It's a bit of a mess, but I'm happy to answer any questions on it or development of the game. Cheers!
EDIT: For those not familiar with PICO-8, there's only a few inputs: arrow keys, Z/C/N, and X/V/M