This is GREAT!
A very fun and clever game. I played it several times til my forearm got tired. 6th place at the moment with 7 million points.
The numbers floating for score make it sooo much harder, but that's a good thing I believe. There's not much to say about it that you haven't already said.
My strategy was to put my cursor in the top left, then use tab to select the start button and start slamming it back and forth as fast as possible til the next one is about to spawn and go down a bit and do the same about 3 times. Then slowly zig zagging in a very organized pattern and HOPEFULLY get your cursor back into the slow track and start over again. I wasn't good at that last part because playing on the couch makes my mouse jerky.
The reason for the tab trick is that if you start the game by clicking, your cursor spawns too low and you lose about 1/5 of the playing field.
Good luck! Thanks a lot for making this game.