The folks at Techland just released an interesting tidbit about their upcoming game Dying Light. As part of the game it will be possible for players to invade the game of other players/groups of other players. That's right at any time during any online game you might go from fighting AI controlled zombies to actual human zombies which ups the ante significantly.
Those that pre-order the game will be granted access to the super-power Night Hunter zombie which will really allow you to terrorize anonymous groups of strangers. I would hope that eventually everyone would get access to the Night Hunter as pre-order exclusives like this are a bit of a down and the night hunter does look pretty bad ass as evidenced by this video.