Luke Skywalker, Darth Vader, Han Solo or Boba Fett are characters that could not be left out and that you can control, each one with his unique special punch. But you will also find other unexpected characters, like a stormtrooper or representatives of many of the alien races of the Star Wars universe.
Despite of having lots of characters, the game is not very special due to none of them having an especially wide range of moves. The animations generally leave much to desire. So to compensate you will have a lot of different game modes, even a versus mode to battle against a friend on the same computer.
Star Wars: The Ultimate Battle is quite an entertaining fighting game. It might not have the best graphics or the best moves list for each character, but it has the unique and inseparable charm of the Star Wars franchise.