Mods introducing new content into the game.
As you research more advanced technologies, earlier products can be made more efficiently. Vanilla recipes remain the same, but new, alternate recipes can be utilized to improve the efficiency of raw material consumption at the cost of higher production complexity. No new items or technologies are added; only recipes are added at various stages of the game.
Small changes concerning balance, gameplay, or graphics.
Designed after the Equivalent Exchange mod (which is now known as ProjectE) for Minecraft. Allows you to convert between any two items in the game at a ratio based on time, energy, and resources required to make the two items. The unit used to exchange items is called MU, or Material Unit. MUs are a global value in a Factorio world. Dematerializers turn fluids/items into MUs. Materializers turn MUs into fluids/items.