Minimalist Retro Shooter

This is my first game. The game is intended to be challenging, and is fairly simple and straight forward. The goal is to score 1000 points by destroying asteroids and other enemy ships. There is a small chance by destroying the asteroids and ships that a power up will spawn which is sure to aid greatly to your endeavors. Enjoy and if there are any suggestions, bugs or improvements you have seen or have in mind, please leave them in the comments. Thanks!