In an interesting move recently, Valve and Capcom decided to exchange characters and enemies in both of their renowned zombie games. Check out some of the gameplay below.
The whole cast from Left 4 Dead 2 will be making an appearance in Resident Evil 6. I think it's pretty cool seeing a move like this. Not only does it give Resident Evil 6 players a new set of characters to play with but I think it opens the door for other developers to experiment with something like this.