Your homeland's precious limited energy is being taken advantage of by the evil Thargoid Empire, and you and your spaceship must do something about it. There are 8 bases to enter, with the aim of using energy pods to cause the reactors to overload and thus malfunction.
The game is viewed side-on, resembling the ST classic Oids quite strongly; which is to say that gravity and motion physics dictate the ship's motion strongly. The 8 levels all have plenty of enemies on offer, both wall-mountings and actual ships, as well as enhanced weapons and extra fuel and shield energy. The ship can take some damage, and repairs itself over time (for no logical reason), which is one of the few things that gives you a hope of getting anywhere early on. Losing a life causes all the enemy turrets to replenish, emphasizing the restart points and making things more maze-based and methodical.