Valve haven't made Half-Life 3 yet because their attempts weren't good enough

Half-Life: Alyx is out today and, as you'd hoped, it is good. Graham-certified good, in RPS's Half-Life Alyx review. For all its goodness, Alyx is not officially Half-Life 3, which Valve still have not made. There are a few primary reasons that the fabled "3" hasn't made an appearance, Valve have now explained. Chief among them, they just weren't happy with what they came up with.

Valve veteran and level designer Dario Casali told IGN today that a combination of "scope creep", cautious tech development, and ideas that just weren't good enough have kept the official third sequel from ever materializing. So far, anyway.

Casali recounts how long it took Valve to develop Half-Life 2 alongside the Source engine. You shouldn't build on shifting sand and, as Valve learned throughout six years of HL2 development, you shouldn't build a game at the same time as its engine.

After finally getting HL2 out the door and feeling as though they had a handle on the Source engine, Valve decided to release new episodes for the game. They'd hoped to release an episode each year, but they got stuck on the number 2 again. Episode 3 never arrived.

"We found ourselves creeping ever forward towards, ‘Well, let's just keeping putting more and more, and more, and more stuff in this game because we want to make it as good as we can,'" Casali says, "and then we realized these episodes are turning more into sequels."

By the time HL2 Episode 2 shipped, Valve were already looking towards development of Source 2 and knew they couldn't repeat the same mistake again "because that created a lot of pain the first time we tried to do that."

More than just technical concerns and a history of ideas that ballooned beyond feasibility, Casali says "we were never really that happy with what we came up with" for Half-Life 3. As a member of the company since 1996, Casali vouches that Valve don't push out projects that don't hit the mark. "Our judge and jury is always the playtesting," he says. "No matter what it is that we're doing, we get validated by that playtesting process, and we stick to that religiously."

In an earlier interview with Game Informer, Valve's Robin Walker said that the studio "absolutely see Half-Life: Alyx as our return to this world, not the end of it." However long it ends up taking Valve to conceive of and create Half-Life 3, it sounds like they're determined that it will be worth the wait.

It may not be Half-Life 3, but Half-Life: Alyx is out today. On Steam, naturally.