Asteroid Defense - space game

Asteroid Defense is a free online flash game of the category space games.

This is Asteroids clone game. The gameplay is extremely simplistic.
The game uses auto-fire so there is no fire button. There are currently three different power-ups: bonus life, gun power-up, and shield. The gun power-up increases your rate of fire and the shield gives you a shield that allows you to take one hit from an asteroid without dying.
The scoring is time-based. The longer you've been alive, the more points you get from destroying an asteroid.

A context menu should be shown when right-clicking or, on touch devices, long-pressing in the game. This menu especially allows to play in full screen and control the volume.