I'll keep this brief, mainly because I'd only be echoing what's already been written. 

So I just downloaded this last night, after having read the review above, and I must say I was very surprised by how fun this game is. I've been looking for a aerial shooter for a while, one that I could just pick up and feel immediately comfortable with. Well this would be it. The controls are easily learned, the difficulty progression is smooth, the weapons are fun and varied, and the enemies are challenging without being infuriating. For $10 this is worth picking up.