In many ways, Payday: The Heist is very similar to Left 4 Dead. You team up with three friends, you fend off hordes of enemies and try to stay alive. But, in a few important ways, they're very different. In Left 4 Dead, a throng of zombies are trying to keep you out of a safe room, in Payday, you rob banks, take hostages and mow down legions of cops. According to a post on the Overkill blog , spotted by VG247 , the Payday devs are working with Valve on a collaboration that will bring both concepts together.

"We are excited to be able to confirm that an in-depth collaboration between OVERKILL and Valve is currently in production." says Overkill director Ulf Andersson. "We are working on a very cool blend of PAYDAY and Left 4 Dead."

A "cool blend," eh. Time to indiscriminately mash Left 4 Dead and Payday's premises together until something works. Zombies robbing a bank? Survivors robbing a zombie bank? Tanks robbing a bank? Crims robbing a bank staffed by Tanks? This isn't working. What do you think it'll be?