So Valve has released this new game, available on Steam, called Alien Swarm. Its a four player cooperative top down shooter. It features eight characters who fit into four classes, and has quite a variety of weapons and accessories. The game play is really solid, the upper difficulties are challenging but not impossible, and the graphics are spectacular. But, the amazing thing about it is that the game is free. Its the sort of game I'd expect to pay at least $10-$20 for, but Valve's released it for free. As it stands, there is only one level that constitutes seven missions, but based on the user interface, it is likely that more will be coming. Not to mention that Valve has released mod tools for the game. Overall, the game is really good, and I highly recommend it.