A trailer for Overkill and Valve’s collaboration Payday: The Heist – No Mercy has been released.

We don’t yet know much about the release other than the fact that it’s an official mashup of Left 4 Dead and Payday: The Heist.

The video shows an attack on Left 4 Dead’s Mercy hospital and was accompanied (before being removed) on Youtube with by text:

"Have you ever wondered how the Left 4 Dead series began? It started with a heist!"

Though the game was announced a month ago, very few details have been unveiled.

Payday: The Heist came out to much critical acclaim in October last year, we’ll keep you in the loop with any details of its zombie brother when they emerge.

Check out the trailer below: