Half-Life 2: Episode 3 doesn't exist because Left 4 Dead does
New Half-Life 2 documentary shows off never-before-seen footage of Episode 3.
As part of this weekend's special anniversary update, Valve has given fans a sneak peek of the cancelled Half-Life 2: Episode 3 project.
As well as sharing stunning concept art and gameplay prototypes, the Half-Life 2 team reunited in the documentary to talk about the development of Episode 2.
The developers also revealed that Episode 3 didn't make it after the team switched focus to concentrate on getting Left 4 Dead "out the door".
"Left 4 Dead needed an all-hands-on effort to ship, and so we put down [Episode 3] to go help Left 4 Dead," explained developer David Speyre.
"It was a really tight shipping schedule and it required a lot of work from everybody to get it out the door. It was worth it - I mean, Left 4 Dead came out great. But it took long enough - and this is the tragic and almost comical thing about it - it took long enough that by the time we considered going back to Episode 3, the argument was made like, well, we missed it. It's too late now. We really need to make a new engine to continue the Half-Life series.
"Now, in hindsight, that seems so wrong. We could have definitely gone back and spent two years to make Episode 3."
The documentary also delves into specific details like weapon design, such as the ice gun that could be used to create cover, ascend over obstructions, or provide players makeshift ledges to get down the side of mountains, and so on.
But at the end of documentary, Valve boss Gabe Newell admitted that one of the reasons Episode 3 never came to be was because his "personal failure was being stumped".
"You can't get lazy and say, oh, we're moving the story forward. [But] that's copping out of your obligation to gamers. Yes, of course, they loved the story - they love many, many aspects of it, but sort of saying that your reason to do it is because people want to know what happens next…
"You know, we could have shipped it. Like, it wouldn't have been that hard. My personal failure was being stumped. Like, I couldn't figure out why doing Episode 3 was pushing anything forward."
The team did, however, reflect that if Episode 3 had been realised, we may not have seen other sequels like Portal 2 or Left 4 Dead 2.
Newell also added that without Episodes, Dota may not have been made.
"If it weren't for the Episodes, there'd be no such thing as Dota. I know that sounds really weird, but it was the things that we learned in developing the Episodes that led to, you know, Team Fortress 2, to more rapid updates."
The full documentary is available to watch online above. Don't forget that to mark Half-Life 2's 20th anniversary this weekend, Valve also released a special anniversary update, bundling in commentary, the previously separate Episodes 1 & 2, and more. Oh, and the game's free to keep over the next few days.