It's not every day that we see the playable release of official Valve content for the original 1998 release of Half-Life. Today is apparently one of those days, even if the "official" content here is a port of a two-decade-old Quake mod that was originally canceled in 2001 and leaked through a 13-year-old hack of Valve's servers.

Confused? Then you should watch this highly informative Valve News Network video, which lays out the story of the Half-Life version of the Threewave mod. If that name sounds familiar, you were probably a fan of the original Threewave mod for id Software's Quake. That mod, released way back in the Internet prehistory of 1996, helped popularize the standard Capture the Flag mode that's been seen in countless shooters since.

Even PC shooter superfans may not remember, however, that a Half-Life version of Threewave was contained in the infamous 2003 hack of Valve's servers —the same hack that revealed an early copy ofto the world. Buried in a leaked folder called "wmods" (in a subfolder named "3wave") was a level pack for's Deathmatch Classic containing replicas of all the official maps from theThreewave mod.

Threewave sees some largely cosmetic changes in the move from Quake to Half-Life—a big polygonal statue "Quad Damage" logo is replaced with Half-Life's iconic lambda, for instance—but the provenance of the core maps is unmistakable. Online discussion suggests Valve was planning to officially release the ported mod in 2001, but the content didn't officially see the light of day until the 2003 server hack (coincidentally, Threewave author David "Zoid" Kirsch was hired by Valve in 2008 and still works there to this day).

The only problem with the Half-Life version of Threewave revealed by the hack was that it was hopelessly broken. Trying to run it online crashed the game immediately, and even running a local version forced you to deal with missing textures and broken spawn points.

That's where Valve News Network's Tyler McVicker comes in. After hearing of the leaked Threewave mod in February (and apparently tracking down a complete version from a Vietnamese FTP server) McVicker worked with a programmer going by the handle PixelMiner to fix the outstanding issues making the mod unplayable. After months of work, the results of their efforts are now playable and available for download.

As a game, Half-Life Threewave looks pretty dated compared to modern shooters, or even decades-old Half-Life 2 CTF mods. Still, the release is interesting as a playable bit of video game history, and it's an intriguing look at an alternate history of what multiplayer Half-Life could have looked like. Intriguingly, McVicker promises "one of these gigantic projects every month until the end of the year," and we can't wait to see what else he's planning to release.