These additions are compatible with the standard characters in the game, allowing the Resident Evil 6 cast to combat the same enemies and partner with the new characters. While playing as these characters, the music tracks used in the stages and results screen are changed to Left 4 Dead 2 tracks. The main cast of Left 4 Dead 2-Coach, Nick, Ellis, and Rochelle-were added to the character roster, as well as two new enemies, the Witch and the Mini Tank. The Resident Evil 6 expansion added content to The Mercenaries No Mercy gameplay mode.
The free content for each game was released to Steam on April 4, 2013. The crossover produced exclusive content for both games. Sometime after Resident Evil 6 was officially announced for PC, Capcom had worked with Valve over the possibility of releasing a crossover between Resident Evil and the Left 4 Dead series.
