this game has loads of potential..
as i am one who loves bikes, i cudnt help but like this game but there are so many things u could do to make this game better, just sit down and look at the game, play it til u get ideas and i promise u right now that they will start flowing. my suggestions:
1. Including difficulty levels that correspond with the level ur on.
2. Definitely try include upgrades, and have the dude start with like a pistol or something, with at the end of each level maybe have the biker stop at petrol station, this is when the upgrade and buying menu comes up and just have loads of variety of weapons on there, plus make other upgrades other than just weapons, such as bike upgrades, different perks maybe.. visual upgrades aswell, so u can kill and look good doing it =]
3. have different types of enemys, maybe each other one with different abilities or something, and a boss level every so often wont hurt.
4. make more lanes, maybe. and have better transactions between each scenery in the background.
5. Could possily have a story line, i know id like that, not sure about others.
6. have checkpoints in between each levels so that if u do happen to die or whatever u can start that level again instead of the whole game, maybe even include a save function.
please dont think im tryin to say ur game is shit, its really not, not at all. i just think it can be muchly improved thats all. And i would love to see it improved