Valve's Steamworks game development tool set has just announced two more PC games that have added to its line-up. Publisher Sega's two big PC games next month, Aliens Vs Predator and Napoleon: Total War, will have support in both retail and digital download versions for the Steamworks suite of features.

That means both games will feature support for things like Steam achievements, leaderboards, matchmaking, stats and the Steam Cloud which lets save games be stored on a online server. Last fall, other download sites like Direct2Drive, Impulse and GamersGate decided not to offer Modern Warfare 2 on their services in part because of the game's use of Steamworks. Indeed a quick check of all three services shows that none of them are offering Aliens Vs Predator and Napoleon: Total War for pre-orders.