Is today "We Love Zombies Day" or something? Adding to our growing list of games featuring the undead and the myriad media we get for them, Valve have thrown out a lifeless bone in the form of an epic trailer for their forthcoming Left 4 Dead DLC, The Sacrifice.

The cool news for this new content is that it's not version locked, so if you have Left 4 Dead you can play it, and if you have Left 4 Dead 2, you can play it too. The Sacrifice merges both L4D iterations together in a story that bridges the overall narrative; opening up the game's lore just that little bit more and creating something of a single universe. And I have to admit, this trailer is pretty sweet.

Watch it embedded below, or click here to download.