Star Trek [App Store] is the latest movie to use a game as a marketing tool, and upfront, if you're a Trekkie, this will appeal to you right away. If you're not, then there are probably better top-down shooters in the world of iTunes.
For a Trekkie, the game offers a fair amount of content and enjoyable gameplay, but the game also doesn't offer anything groundbreaking that you haven't seen with similar games. The basic premise is that Capt. Kirk and his crew must destroy enemies of the Federation and do so in enemy space on board of the U.S.S. Enterprise.