Valve's Achievement Sets beta finally lets completionists track base game progress without DLC expansions tanking their 100% status. Developers can now group achievements into separate collections—base game sets stay blue and count for everyone, while DLC sets appear purple only for owners and stay out of the overall tally until purchased. Seasonal or time-limited achievements can be archived so long-gone events don't leave hidden trophies dangling forever.

The updated achievements page shows overall progress alongside per-set bars, adds search filters for locked or unlocked items, and lets players compare totals with up to three friends. A 'set complete' trophy marks finished buckets, and prior completions stay locked even if new achievements get added later. Seventeen titles already support it, including Portal 2, Team Fortress 2, Left 4 Dead 2, Forza Horizon 5, and Call of Duty: Modern Warfare 4.

Steam Client beta participants can test the feature now, with Valve rebuilding the Steamworks editor to make set management easier for devs. This directly addresses the long-standing complaint that post-launch content quietly ruins perfect records without warning.