Steam's Achievement Sets beta, now live in the client, lets developers partition achievements into distinct collections so DLC expansions no longer retroactively tank a player's completion percentage.

Base Game sets appear in blue and count toward overall progress while DLC sets display in purple and only factor in once purchased, preserving prior 100% status even as new content arrives. Completed sets lock in their trophies permanently, seasonal or expired achievements can be archived without affecting existing unlocks, and the refreshed achievements page adds per-set progress bars plus comparison against up to three friends.

Seventeen titles already support the feature, including Against the Storm, Crusader Kings III, Euro Truck Simulator 2, Forza Horizon 5, Portal 2, and Team Fortress 2. Developers must implement the sets themselves, and Valve continues iterating during the beta period.

This addresses a long-standing pain point for completionists without requiring Valve to police every future DLC release.