Gotham Knight - or the Batmanamatrix, in reference to the notion it emulates the Animatrix, referencing the same continuity but ultimately being of little true consequence to the film that precedes or succeeds it - is the newly released Batman animation.

The six stories told are without a great deal of overlap... being as they are, simply set in the interim between the end of the last film and before the beginning of the Dark Knight... suffice to say that while the style varies between them that the animation is all of a suitably high quality - although, it's rather strange to see the slightly different realisations of Batman and Bruce Wayne, as they're all voiced by the same voice actor.

The stories vary considerably - from Batman testing out a magical bullet shield (which is fortunately one of the shorter stories and where Batman quickly rejects the device), to Batman saving cops from a mobster shoot out all the way through to Batman and Deadshot facing off. The Animatrix seemed to flounder because of it's different directors and styles... and the Animatrix was essentially just a way for the Wachoski Brother's to introduce the irritating hero-worshipping Kid and explain how Zion was aware of the Machine's digging.

Gotham Knight doesn't have any stories that are facilitated by a particular plot need. They're presumably just what the writers thought would be cool... and it works and even if you find one of the stories dragging a bit, you've always got the prospect of another one just around the corner... all in all, an excellent way to whet the appetite for the new Batman.