Here's the "basic lowdown" on Rebel Strike from EGM:

• The game begins right after the battle of Yavin. From there you can choose one of two characters. If you choose Luke Skywalker, you'll play more on-the-ground missions ripped directly from the movies (i.e. Taking out AT-ATs with your light saber, speeder bike missions on Endor). If you choose Wedge Antille, his campaign focuses on flight missions; his plot is more between-the-scenes content not direcly taken from the movies.
• There's going to be more bonus levels this time around, and the developers stated that it won't be so insanely impossible to unlock them.
• Multiplayer content: The entire RS2 game will be available to play via splitscreen co-op in RS3. It doesn't end there though, Factor 5 stated that there may be a Versus and Capture-the-Base modes for at least two (maybe four!) players.