alienswarm Recently, Valve took a page from stores that release free e-books, such as Baen or Amazon: it released a complete game, and all necessary development materials for the game, entirely free through its Steam digital distribution system. Alien Swarm, from the development team hired to work on Left 4 Dead and Portal 2, does for the Ridley Scott/James Cameron bug-hunt genre what Left 4 Dead did for George Romero and zombies. Players take on the role of one of four space marines investigating a colony overrun with slimy alien creatures. It is a complete, if short...