If you see something in green, protect it. That's pretty much it in a nutshell. This is perhaps the biggest flaw of the game, as there is no variety whatsoever. Every mission is pretty much the same, namely seek, destroy, protect by destroying. This is great fun to start off with, blowing things up and flying around in the vast infinity of space, but soon leaves you craving for some different mission styles, such as limited ammo or even a planet-based mission.
First impressions are very good.
You have a choice of four battle fighters initially, but as your rank increases new craft become available. Each ship has its strengths and weaknesses, be it sacrificing speed for shields, or guns for acceleration, and a veritable arsenal of lethal weaponry. This armoury can be customised to suit your particular fighting style. You may prefer having extra fuel for your afterburner, allowing you to get to your next target more quickly. Then again, you may be of the ilk that prefers brute strength, so you can dump your fuel for an extra Jackhammer missile.