It's Super Metroid meets G.I. Joe. Was a bit short, even while retrieving 100% of the collectibles, but not enough so to feel ripped off. Overall, definitely worth the money, as this is one of the better XBLA games.
Puzzles were really quite fun. I liked the creative (and sometimes frustrating) use of different game mechanics in each world to give them each variety.
This game is HUGE! You can spend hours getting lost in the wastelands. Love the freedom that it gives you, while forcing you to live with the consequences of your actions, both good and bad.
Took a simple game and found many different ways to spice up the gameplay. Certainly a step forward from it's predecessor. If you like shmups, you'll love this game.