Where the hell is the sound?
You lost half your marks for having one NO sound effects and two for having no BGM.
This game lacks challenge, if you made the screen scroll at some speed WITHOUT the controlling doing so it would be make it more interesting. Also I honestly wonder what the goal is.
Why the hell would anyone have a motorbike that launches Tennis Balls from the front at whatever those weird red things are?
If you made some sort of story like your been attacked by Aliens that look like red frisbees and they just so happen to be immune to every weapon you can throw at them except tennis balls now that would draw a higher score.