The DC Heroes role-playing game had a Watchmen module that included information supplied by Moore that wasn't in the original story. Whether Moore wrote this specifically for the game or they just used his notes, I don't know. But at the time die-hard fans of the series picked this up. It took place prior to the passage of the Keene Act that outlawed the heroes. Pretty sure Dave Gibbons supplied original art for the modules. The author is Ray Winninger.