According to an announcement on the Half-Life website, Valve has just released the 25th Anniversary Update for Half-Life, which adds a ton of new content, some quality upgrades, and even SteamDeck support. And best of all, you can download the game for free for a limited time.
Let’s take a look at what’s new first. The company says the game now includes Half-Life Uplink, a "mini-campaign" that was initially only available through magazines and on discs from hardware manufacturers. There are also four new multiplayer maps, which Valve says "pull the limits of the Half-Life engine." Valve also added maps and multiplayer character models from a disc called Half-Life: Maps and Multiplayer Character Models from the FurtherData Disc.
Additionally, Valve has added some new features to the game, including widescreen FOV and support for "proper gamepad configurations." The game's user interface has also been updated and can be scaled to fit larger screens. (Valve says, "We designed most of the interface for the 640x480 tube, but apparently some of you have already upgraded.) Half-Life is now SteamDeck Verified, which means it will run on SteamDeck without any action. On the just-launched SteamDeck OLED, this could be a great game!"
This is indeed a very important update for Half-Life fans, a detailed list of all the changes and patch notes are below:
https://half-life.com/en/halflife25
A few final important notes: Valve says the Anniversary Edition is now the "definitive version" of Half-Life, but older versions of the game are still available on the "steam_legacy" test branch. Additionally, Valve will "reduce the visibility of Half-Life: Origins."
After reading the patch notes, you can watch the new 25th anniversary documentary that Valve just uploaded to its YouTube channel (it's directed by Danny O'Dwyer, who you may know from Noclip).