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.