There are 3 locations in the game. First Geonosis - the rocky planet home to bug like Geonosians. There you will encounter Geonosians and all the types of Battle Droids. The next location is the metal structure of an abandoned assault ship, where you will meet Battle Droids, hovering Scavenger Droids and reptilian Trandoshians. Finally on Kashyyk, you will meet Wookies, who are your allies, and Trandoshians, Scavenger Droids, Genosians and Battle Droids who are your enemies.
It is a great game with levels that don't get old quickly. Also the levels don't get too frustrating. I love it.