Left 4 Dead is one of the most beloved co-op games ever released. Valve's four-player squad-based first-person shooter was a huge hit among fans when it was first released back in 2008.

A sequel was released just a year later in 2009 and both have remained many gamer's go-to titles whenever they want to go and destress by killing some zombies. However, while both Left 4 Dead games remain just as playable today, one can't deny that they're starting to show their age a bit.

Thankfully, the original developers of Left 4 Dead, Turtle Rock Studios, decided to give fans an updated version.

Turtle Rock Pays Homage To Left 4 Dead In Latest Back 4 Blood Trailer

While Back 4 Blood isn't a true sequel to Left 4 Dead, it is a spiritual successor made by the same people, and at Warner Bros.' E3 2021 conference, fans were treated to a closer look at the PVP-focused mode, Swarm Mode, where the cleaners (humans) and the ridden (infected) face off. Humans and the Ridden Go Head-to-Head in Back 4 Blood's Swarm Mode In a battle between the alive and the undead, who do you think will reign supreme?

In Swarm Mode, players can choose to play as either the ridden or the cleaners. To survive, the cleaners will have to stick together. Communication is key as each downed player adds to the total tally of the ridden on the map. The more cleaners that die, the more ridden there will be to encounter until the cleaners find themselves overwhelmed by the sheer number of the infected.

The basic premise is that each group will have a limited time per round to kill the opposing side as fast as possible. Every round, the sides will switch and the clock starts again.