After a few false starts, this was excellent. Loved the art, SFX and retro vibe... though I must admit to getting bored after passing 10,000. Kept expecting some incrementing phases (vertical barriers, jumps, other road users, police chases?)
There definitely needs to be some more difficulty spiking. I like how you termed "incrementing phases" -- some extra variety would go a long way to keep the difficulty engaging after you figure out the bike behavior.
