As of February 6, Bay 12's Dwarf Fortress has sold over 600,000 copies within two months. 

According to Tanya Short of publisher Kitfox, the construction roguelike has been a "very good success," which may be understating things. Within its first day of release this past December, it hit Kitfox's two-month sales goal, and it was recently revealed Bay 12 has earned over $7 million from the game's commercial reception. 

Dwarf Fortress has been in development and Early Access for over a decade. It had more than enough time to earn a devoted following before the official release, and word of mouth from that player base further helped draw attention (and sales) to the game. 

The majority of Dwarf Fortress' sales are from Steam, naturally, but Short acknowledged that 5,000 sales came from itch.io. Since Bay 12 is a small company made up of only two people, and that platform allows for a more fair revenue split between developers and publishers, the duo behind Dwarf Fortress stands to see more money from individual purchases on itchio.

In her breakdown detailing Dwarf Fortress' sales, Short credited Steam with the game's initial 48-hour success. Direct navigation to the Steam page made up 4.6 million (or 37 percent) of total visits, followed closely by Steam emails about new releases, which came to 3.2 million (26 percent).  

For Steam's home page and pop-up window, impressions were respectively at 22.3 million and 13.84 million, meaning that any time you booted up Steam, there's a good chance Dwarf Fortress was the first thing you saw.

Short noted that the pop-up window was the first Kitfox-released game to get that treatment on Steam, and was received on the game's second day of release due to "kind Valve support." 

Beyond Dwarf succeeding on its own merits as a great game, Short pointed out that Kitfox's multiple strategies that further helped the game success. From allowing Bay 12 to be transparent during development to suggesting features be cut in favor of the game retaining visibility, she believed those actions were the right call in the end.

"I’m so genuinely proud that we were able to help Tarn and Zach achieve a new level of success," Short wrote.