I bought Rage from an online store yesterday. I activated the game and its DLCs (Anarchy Edition and Sewer Missions). After activation the game showed the popup: Game already registered. And ...
I have not encountered any Sewer Missions on job boards while playing through RAGE. The Wiki only describes the Wasteland Sewer Missions as X360 DLC. However in game properties in Steam I can see ...
So it's been a while since I've used Steam but I found somewhere on the web I had to validate a game before I could play it offline https://support.steampowered.com/kb_article.php?ref=3160-AGCB-2555 ...