I saw people talking about this game on a few forums, but never really had any interest in it till I saw it cheap on eBay and bought it on a whim. I'm so glad I did, the game is just pure fun on a disk.
The game is a budget release, so don't expect state of the art graphics, top quality voice acting and for the game to run without the odd hitch. The story revolves around trying to repel an alien invasion force which so far consists of giant ants, giant robots, giant spiders,(see where this is going) giant spaceships, motherships and a gigantic robot that I have no idea how to kill. To do this you get a wide array of over the top weapons with unlimited ammo to fight your way to victory. The enemies come at you hundreds at a time and gives the game a very Serious Sam feeling. The whole game can be played in Co-op offline, but I haven't had a chance to try it
So if I haven't convinced you by now here's some screens
Great review which pretty much sums up my feelings: http://www.eurogamer.net/article.php?article_id=74994