https://www.pcgamer.com/frostpunk-studio-commits-to-expansions-as-sales-hit-250000-in-three-days/

The masterful misery simulator Frostpunk has already sold 250,000 copies, developer 11 Bit Studios said today, meaning that it's already covered its development and marketing costs and is now sailing the warm blue seas of profitability. It also means that expansion content, including free updates, is now guaranteed to happen. 

"We plan to polish some rough edges of the original game—you're reporting some issues with difficulty balance, with minor bugs and such. We want to fix that! We also plan to add more modes and scenarios to the game," the studio wrote in a Steam update. "It's too early to announce [specific plans]—but you should be excited. And yes—a sandbox/endless mode is on our mind as well. Frostpunk is going to grow - all you have to do right now is to wait a little bit. We do plan to release a roadmap for our development plans as soon as we're ready."