This review takes me back to when I would play this game with my friends in primary school (multiplayer)...good times!
Anyways back to the review...I got this game quite soon after I got my PSP in 2006. It has both a campaign mode where you try to conquer star systems with a combination of space battles initially then the conventional on planet battles. After a certain number of kills on the planet you unlock more characters for that round (more powerful ones), e.g. on Endor you can unlock Han Solo if playing for the rebels or Darth Vader if playing for the empire.
The other mode is if you choose a battle on a particular planet with a particular objective such as capture the flag or if you are playing on mos eisley there is the hero mode where you can choose Jedi or Sith and play any of those good or evil characters.
This game is something that once you get used to playing you will be able to play it and enjoy it for years. I still play it on my PSP E1000, after my original console got damaged.