Furnace is an engine-building Eurogame in which players take on the roles of 19th-century capitalists building their industrial corporations and aspiring to make as much money as they can by purchasing companies, extracting resources, and processing them in the best combinations possible.

Once all the cards have been claimed or discarded, players enter the production phase, using their cards in the order of their choice. Each company card has one action — either production or processing — on its basic side and two actions on its upgraded side. During the production phase, you can use each of your cards once to gain resources, process those resources into other resources or money, and upgrade your cards.

Furnace also includes capitalist cards that contain unique effects, and if you want, you can choose to deal one out to each player at the start of the game. For an additional challenge, you can require players to create a "production chain", with each newly acquired company card being placed somewhere in that chain and locked in position for the remainder of the game.