This game is about an American Indian named Tommy who's girlfriend runs a bar and the two as well as his Grandfather are all abducted by aliens.
While the story is a TAD silly sounding, the story is told very well. Not only does the trio get abducted but the ENTIRE BAR gets abducted as well. You run into it after a couple levels.
The guns are all made partially of organic material (grenades are little green 3 legged guys even) and sound disgusting but feel really good.
The gameplay is a bit like Portal's. You'll find portals in ther world that go from one place to another spot in the same room (a similar concept to Portal). You don't have a portal gun like in Portal though. A lot of times you play with gravity and end up walking on walls and ceilings. Sometimes you'll walk into a room and start fighting baddies on both the ceiling and the walls at the same time. And there's gravity spots that change gravity in the room from the walls to ceiling, floor, and so on.
The story is the most interesting part to me. Tommy wants to get away from the Reservation and start a new life of his own. His girlfriend only wants to stay put and have a quiet life. Tommy's grandfather wants Tommy to embrace his heritage, while Tommy just wants to have his own thing.
They're all abducted and Tommy gets separated from his loved ones. He then escapes and over the course of the game you set out to find your girlfriend and get back to Earth. After a while you learn that It's not just a couple people being taken, and you set out to also stop the invasion.
While the voice acting of Tommy isn't perfect ( it IS an FPS after all...) his performance is very sincere and that comes through in my opinion. Plus when something big happens he comments on it or if you beat a huge boss he'll shout and celebrate just like you are doing. This is one of the most interesting First Person Shooters I've played in a while and I HIGHLY recommend you check it out. I started playing yesterday and I can't stop thinking about the game. I don't wanna stop playing, and with a game...that's kinda the point isn't it? I'd say 9 out of 10.