The most reliable "old school" method is finding a physical PC DVD copy. Because the game used Steamworks , even a physical disc usually requires activation through a Steam account.
You can no longer simply "click buy" on a digital store to download it. How Players "Download" it Today Download R.U.S.E. PC Game 2010
If you bought the game digitally before 2015, it remains in your library. You can still download and play it as usual. The most reliable "old school" method is finding
If you go looking for R.U.S.E. on major platforms today, you’ll run into a significant hurdle. In , Ubisoft officially removed the game from Steam and other digital storefronts. Download R.U.S.E. PC Game 2010