For a used game price of at least 8 doallars you can't go wrong. Its fast, action packed, and at times dizzying. :)
The game stars Tommy, a Cherokee who dreams of taking his dream girl, Jen, to the outside of the Indian preserve where se owns a bar. His Grandfather, Inisi, warns him of an evil that is approaching. Soon strange lights envelop the bar and Tommy, Jen, and Enisi are sucked away to a massive planet-like sphere. Tommy is broken of his transport device by a mysterious man who blows up the track that his device is on. From here you gain your first weapon and the true game begins. The game features some incredible visuals for an early 360 title. From the pulsing live walls that you are mostly moving around in at the start, to the fact that most of the weapons you are using are alive and moving nearly all the time. Moving around the sphere has some interesting twists in the form of Portals and Gravity altering paths that allow you to walk on the ceiling and walls. A great little thing that was included in the game are News Broadcasts that are recieved through these monitors that have a picture of Earth on them, they are all really cool to listen to and I advise you stop and listen to all of them, one you will have to search a bit for. Through the course of the game you will collect a multitude of different weapons like the Rifle which can also be used as a sniper rifle, The Assault gun which has a grenade launcher on it, and the grenades themselves which are actually little nippy crab like creatures that you rip the limbs off of to trigger. Eventually you gain the ability to "Spirit Walk" which allows you to seperate your spirit from your body and use a Cherokee Bow to score some good kills. This also comes heavily into play to solve puzzles later. You also gain an ally in the form of Talon, a Spirit Hawk who can distract enemies and translate the Alien Language on screens and moniters by landing near them. When you die you are transported to a strange area where there are these blue and red spirit things flying around and your body hovering in the center. You have to shoot at least 1 red spirit to recover some life to your body, but you can shoot as many as you want. After your body goes through the hole in the ground a suction will eventually pull you back down into the game with however much life and spirit energy you gained from the spirite. Your enemies include Alien Hunters who can teleport in at what seem to be whenever, these strange Dog like aliens that can scare the crap out of you if you aren't expecting them, and altered humans who are forced to work on the sphere. There are many more enemies but you'll need to play the game to see them yourself. You will also employ the use of a Shuttle to fly around a shoot at enemies, and even go to small planetoids which have their own gravitational pull. Will you save Jen? What is this "Sphere?" Will you ever get back home? Or will you become Prey for your adversaries?
There's also an online mode but there aren't many people on at one time. Its still fun when you can find it and the game is pretty well balanced online, except when there are Shuttles involved.
All I can really say is for 8 bucks its a steal. Buy it if you see it. TRUST ME!