This has the potential to be one of the best games in the App Store, if only it would add some sort of story/campaign mode. It has the feel of some of those older space simulaters like TIE Fighter or X-Wing, and with a story, could be awesome.
As it stands now, it's a very fun, very well designed game with great controls and graphics. I had no problems at all with the control scheme, it felt natural, you manuever the iPhone/Touch around and the ship follows, very smooth, very responsive.
It also has a very satisfying increase in the level of difficulty. Whereas some games here go from easy, to medium to hard in as few as 3 or 4 levels (I'm thinking: Topple), this game gradually increases in difficulty, starting with Space Mine which threaten the station but not you, to raiders and alien ships that have it out for you in amazing numbers.
Which leads me to another complaint, I haven't really played recently because I was showing a friend the game and he mistakenly pressed "New Game" which erased my current progress (said 20+ levels), meaning I had to start back at square one, which is basically a tutorial. A save feature on this game would be very, very nice.
But it is completely worth the $3.99, it's fun and it looks good.
(It does, however, being a 3D game, drain the battery)