In comic books, crossover events between two super hero universes are considered to be a huge deal. Remember when Superman met Spider-Man? When Batman met Predator? When Archie met The Punisher? Well two of Valve's game universes are about to have a (tiny) crossover of their own.

The deal is if you pre-order Valve's upcoming zombie shooter sequel Left 4 Dead 2, not only do you gain early access to the game's demo and pay 10 percent off its regular price but if you also happen to own Valve's multiplayer shooter Team Fortress 2 you get an extra in-game bonus. It's Bill's hat. Yep, now your TF2 characters will be able to wear the same hat design Bill has for Left 4 Dead 1. Hopefully this is a sign of things to come. The Heavy mowing down the Tank in a game? We would love to see that.