However, upon further scrutiny of the main game directory in Valve’s Source 2 game list, one of the key titles that were also found is “Left 4 Dead 3.”
Basically, having the upcoming Valve video games on Source 2 engine means that they would be faster and their graphics more detailed.
Turtle Rock Studios was the first to conceptualize “Left 4 Dead” before Valve Corporation bought in to the project and they collaborated with its development and officially released it to the PC and Xbox 360 in October 2008.
They continued the collaboration with the sequel “Left 4 Dead 2” which significantly earned a greater level of success than its predecessor when it was released in the same gaming platforms in November 2009.
However, Turtle Rock recently announced that it will no longer be involved with “Left 4 Dead 3” and is leaving everything to Valve.
Turtle Rock co-founder Phil Robb confirmed in a February interview that they are pretty much done with the “Left 4 Dead” video game series.
2105 seems like a reasonable date for this announcement.