Good game, please consider the following modifications/additions:
- An in-game tutorial
- A settings menu for audio and input rebinds
- A main menu
- Ability to pause and continue playing the game
- A larger combat zone
- Make shooting/aiming less punishing (easier)
- Introduce different type of enemies
- Make the game harder as the player progresses
- Add upgrades to the ship and/or different types of ships that can be purchased using points
- Add online and/or offline multiplayer to the game
- Add levels and bosses to the end of each level, and based on the points the player earned he/she will progress to the next level.
- Add different types of asteroids to the game with different sizes and properties (e.g. mass, speed, etc).
- Make the environment more interesting by adding planets or stars.
- Try giving the player more satisfying feedback when destroying an asteroid or getting points rather than using sounds and simple visual effects.