Good use of physics, good idea a little slow paced
Starfire is another classic scroll down game, im sick of having the same old simple scroll down fighter simulation games, with this however you can upgrade your ship by collecting floating (rather strange) credits, the way in which the AI actually interacts with the user whilst playing the game is a good idea, then again theres not much you can do for interaction with a scroll down game such as this.
I personally think that the storyline could be a bit more and longer, but other than that good 'borrowing' ;P
the different upgrades for the ship such as Shields Hulls Generators etc brings this games uniqueness, and as for the homage to the classic scroll down games such as Radien, i think your just about there