I don't understand exactly what I supost to do. If is your first game ever made, well, keep trying, I can't judge much.
Some hints to help on next project:
- Visual feedback always welcome, like, if I shoot and hit a enemy, make something to happen to him, like make him blink or change their color for one second
- Control is very important, the car direction for this game, it's not help much
- If the player have some kind of limit resource, like life, show then somewhere in the screen, like X2 or two heart.