Left 4 Dead 3 would've been open-world on Source 2 - TweakTown

Back in 2013, Valve was working on Left 4 Dead 3 alongside a myriad of other projects--including a unique Half-Life 3 idea.

Now Valve opens up on what Left 4 Dead 3 looked like back then, and discusses why the game wasn't ever released.

Back in January, Valve said it wasn't working on Left 4 Dead 3, which was technically true at the time.

"Every other playtest, pieces of your base would go missing, and zombies would float in," Valve programmer Don Holden, who had worked on Left 4 Dead 3 in 2013, said in the documentary.