Difference Engine is one of the Technologies in Frostpunk. It is necessary to unlock the fourth tier of technologies.
The Difference Engine technology is the fourth of 5 special technologies which do not unlock anything directly related to the game world, but instead allow the researching of other technologies by expanding the Workshops' capacity to research. The technology following Difference Engine is Automatic Prototyping. The prerequisite to researching Difference Engine is Mechanical Calculators, having any workshops with working engineers, and 125 Wood and 75 Steel.