Each player picks one of 27 characters -- including about 11 costume-variations on the single-player apprentice -- and the fights take place in nine Star Wars locations. The characters include a young Luke, Darth Maul, General Grievous, and others that don't related to The Force story. And their moves are all about the same as in the single-player game, so Luke uses the lightning strike alongside the "dark" characters.
The match locations impact the the fights, with players instantly losing a life if they fall into the sarlacc pit, Smash Bros.-style. Otherwise, Hoth, the Jedi temple, and other locations include objects to toss around at each other, giving each location subtle differences.
These setting, and deep attacks, counter-attacks, and blocks should add a lot of ways to play these match-ups. This variety makes me anticipate its September 16 release. Plus there's a whole other single-player story to beat.