It looks as though the Overkill and Valve cross-over project with left 4 Dead undertones is the No Mercy map.
According to a video posted by Overkill, and hastily removed, the video shows the bank robbers from Payday: The Heist inside the hospital from the first L4D campaign.
Speaking with Kotaku, Valve’s Chet Faliszek said players will see one of the L4D characters in the hospital and a “fun little easter egg with a payoff later in Left 4 Dead.”
Faliszek said this was Valve “having some fun with a studio we are friends with and who have also made a great co-op game.”
“This is a 100% Overkill made mission for Payday: Heist simply set in no mercy hospital from the Left 4 Dead series,” he said. “It is not telling the origins of the Infection and is not canon.
As mentioned above, the video was removed, but not before someone else pulled it. Watch it below.
A released date for the map hasn’t been announced.