Really fun and creative idea, congrats. The name is gold too ;D Everything works nicely, and it's fun to try get what are the best upgrades, and upgrade order.
The only thing that isn't too clear to me is how to "collect" time: it seems I have a bonus each lap, but couldn't get it fully at the first run... I think!
Thanks for this awesome little game, I wasn't expecting it to be for free!