The engine is solid, music is a good chiptune choice but repetitive after a while. I would add other types of bikers, random cars and divergent road paths. You could code the next Spy Hunter!!!
It controls well and simply, like classic Nintendo with a mouse.
Put in some powerups like a shmup instead of the typical guns and you'd have something grand. Keep the sense of speed you have in the background and maybe make a penalty for driving off the road like hazards or guardrails to crash into.
I like it. Take it further.