Nice, simple game. It does get a bit over repetitive, so I'll offer a few suggestions (for what they're worth) for if you want to make a sequel. In the end though it plays well and looks nice so it is well worth 4 stars.
1. While I got used to the idea that touching the roof counted as a "crushed" it is extraordinarily sensitive. Surely you could survive a light grazing?
2. The flip sensor should be more generous - a flip should count as a 360 relative to flat ground rather than from your take off position. They are rarely worth attempting as it is.
3. Maybe have randomly located temporary power-ups, like a roof spring (good for saving you from being crushed once), suspension grease (makes you jump higher for a time) or turbo boosts.
4. You should get credit for pulling wheelies.
5. I think you should have a rethink about the music. On mute the game has a vibe of sombre futility (in a good way) - you're driving at dusk / dawn to nowhere, for no reason. But then the music is all rinky-dinky frivolity. Maybe something inspired by Sandy Bull or John Fahey would be better.
6. You should get a better idea of what you're driving into - like have a small bar at the bottom that displays two or three screens ahead, so that you can plan your jumps and tricks rather than being purely at the mercy of fortune with how and where you land.
Just a tip to those who are playing the game and running out of gas - you should be using the hills and divots to jump and earn air time points and you don't need to accelerate while in the air.