Half-Life 2: Episode Three
Half-Life 2: Episode Three became the holy grail of vaporware once the 14-year-old development journey of Duke Nukem Forever ended in 2011. For a quick history on the supposed trilogy, Half-Life 2 released in 2004, six years after the original Half-Life. Valve would then announce a trilogy of Half-Life episodes, with each episode considerably shorter than a full game but released in a shorter time than a full title.
So Half-Life 2: Episode One released in 2006, two years after Half-Life 2, then Half-Life 2: Episode Two released a year after that. Then nothing.
Valve has since launched seven games after Episode Two and The Orange Box collection: Left 4 Dead, Left 4 Dead 2, Alien Swarm, Portal 2, Counter-Strike: Global Offensive, Dota 2, and The Lab. Also, Steam became a juggernaut of a platform for digital game distribution.
Cue a full decade of “Valve can’t count to three” jokes and here we are. Not much is officially known about the future of Half-Life, but the history of leaked images and information has been extensively collected. Even an ex-Valve writer wrote a possible outline for the next episode, describing it as “fanfic” and “a genderswapped snapshot of a dream I had many years ago.”
Though Episode Two ended on a cliffhanger that left its fanbase rabid for more, people would forgive and still buy it after all this time. It all depends on when Valve is ready.