Payday: The Heist - No Mercy sets the scene for Left 4 Dead [Update: It's 'not canon,' Valve clarifies]

Payday The Heist  No Mercy sets the scene for Left 4 Dead
A trailer posted by Overkill Software (since pulled) revealed the collaboration between Overkill and Valve as Payday: The Heist - No Mercy, a Payday game (either a new standalone release or a DLC expansion, it's unclear which) that crosses Overkill's heist series with Left 4 Dead.

The trailer reveals that the episode will act as a prequel for Valve's zombie shooting series, with a heist in Left 4 Dead's Mercy Hospital. "Have you ever wondered how the Left 4 Dead series began?" the YouTube description asks. "It started with a heist!" So by playing this, you'll very likely trigger the zombie pandemic in those two games. Real nice, butterfingers.

Update: Valve's Chet Faliszek has clarified to Kotaku that the YouTube video isn't a prequel, saying the video description was the work of "some over-excited marketing guys." The map is a Overkill mission "simply set in no mercy hospital," he says. It is not part of the Left 4 Dead narrative in any way.

This article was originally published on Joystiq.