No revenue estimate for GOG — its rating/review counts don't calibrate to sales the way Steam's do. The Steam version is estimated at $6.3M — a different platform, not this one.

Stronghold: Warlords

For the first time ever Stronghold: Warlords allows you to recruit, upgrade and command AI lords across the battlefield in the form of in-game ‘Warlords’. Each warlord under your command boosts your strategic prowess with unique perks, characteristics and upgradeable abilities. Put them to work for your industry, fortifying borders, forging weapons or team up for a pincer attack! Each campaign mission, skirmish game and multiplayer battle means a fresh set of warlords to command and a completely new way to play Stronghold. The next chapter in Firefly Studios' real-time strategy series, Stronghold: Warlords is the first game to recreate the castle economies of East Asia. In Warlords players take command of Mongol hordes, imperial warriors and samurai clansmen as they lay siege to Japanese castles and fortified Chinese cities. Besiege historical warlords using new gunpowder-fuelled siege weapons and classic units across 31 campaign missions, multiplayer, skirmish and free build modes. CONQUER AND COMMAND WARLORDS across the battlefield unlocking more powerful castles, armies and abilities. RELIVE HISTORICAL CAMPAIGNS from 3rd century BC China, to the rise of the Tokugawa shogunate and coming of the Mongol Empire. RECRUIT NEW UNITS including imperial fire lancers, disciplined samurai, Mongolian horse archers and deadly ninja. RAZE YOUR ENEMIES with the arrival of gunpowder and new siege weapons like the hwacha arrow launcher, siege tower and fire oxen! BECOME THE GREATEST LORD through fear or admiration using a range of medieval entertainment, taxation and torture. Please note: The GOG GALAXY client is required to access online features and additional skins for Stronghold: Warlords. Multiplayer is available only between GOG users.