Great, great game. Buy it, you'll be glad you did.
Just some of the best features are:
-Multiple planets to travel to (Including the Space Pirate Homeworld)
-Switch between the combat, scan, command, and x-ray visors to solve puzzles
-Extensive morph ball gameplay to add another dimension to the game
-Harrowing boss battles (Including 2 against ridley!!!)
Definately the best of all 3 prime games, and I loved them all.