While some third-party sites may use "free download" in their titles to attract traffic, the official versions on major platforms require a purchase:

is generally a paid real-time strategy game and is not officially available for free on standard storefronts. Where to Get the Game

Listed on the Nintendo eShop, Xbox Store, and PlayStation Store. About the Game Save 80% on Bad North: Jotunn Edition on Steam

Can be purchased on Steam or through the Humble Bundle Store .