Yesterday, Half-Life 2 received a 20th Anniversary Update on Steam, bundling content from the graphics demo expansion Lost Coast, as well as Episodes One and Two. This content was made free to claim until November 18. For other contents of The Orange Box bundle, which still includes all these titles standalone for certain mods, as well as Portal and Team Fortress 2, the entire bundle can be bought for just $1.99 until November 22.
Most Half-Life 2 mod support will now be rolled directly into the main game alongside the Episode One and Two expansions, including all the Achievements once included with those formerly standalone titles. While The Orange Box bundle still consists of the standalone for Half-Life 2 expansions, these store pages are now delisted in search results, and the standalone executables are now moved to the "Tools" section of Steam games.
This Half-Life 2 20th Anniversary Update does more than streamline expansion support, though— Half-Life 2 has been fully overhauled within the constraints of its original engine, seeing all Half-Life 2 content updated to the level of Lost Coast's fidelity or better and even getting deeper integration with modern Steam features including Game Recording event markers.
Besides the updates to and past Lost Coast's fidelity level, including the addition of a Source engine HDR pass to every map, the biggest signs that this is a 20th Anniversary update are the addition of a new High Quality mode that renders all models at full-quality LODs regardless of distance and bicubic filtering, which enables smooth shadows when Very High shader detail is enabled.
For those unfamiliar, "HDR" in the context of the Source Engine doesn't refer to modern-day DisplayHDR (though you can still experience that when playing this update if you're playing on a display and version of Windows that supports Auto HDR) but instead, an engine feature that essentially pre-bakes some Global Illumination into lighting, reflection, and refraction calculations.
While it's not Real-Time Ray Tracing, it dramatically amplifies the fidelity of lighting realism and water effects in Half-Life 2: Lost Coast and has now been retroactively applied to all prior Half-Life 2 games. This is in addition to several common map design elements, including fences getting updated to cast shadows, among several other realism-oriented map design changes throughout Half-Life 2 and its expansion Episodes to present an ideal vision of Half-Life 2 and its era of the Source engine.
Other changes and improvements to the Half-Life 2 package are mainly related to UI quality, implementation with modern controllers and input methods via Steam Input, and Steam Big Picture/Steam Deck support. Three and a half hours of developer commentary has also been added to Half-Life 2. For a complete list of changes and links to related behind-the-scenes content, check out the official Half-Life 2 20th Anniversary page.