Orion Defense

This is a space-themed tower defense shooting game with three levels of play. After completing all three levels, you can unlock the infinite mode.
The first level is a tower defense game, where you build and upgrade turrets to automatically attack and destroy enemy fighters. You can also manually control laser turrets to destroy enemy capital ships.
The second level involves piloting fighters to destroy enemy fighters and a fleeing capital ship.
The third level involves piloting fighters in the asteroid belt to chase down the enemy commander, while avoiding asteroids.