Dig beneath your planets. Freight Elevators sink shafts to caves three levels deep under Nauvis (four with Space Age, plus one under Gleba and one under Fulgora, and 2 under Aquilo!) The ore above runs on below; deeper down come granite, quartz, feldspar, geothermal heat, and higher pressure, guarded by Underground Horrors. New buildings, new enemies/combat, new defenses! Supplementary to Space Age, no required technologies but lots of less expensive alternatives. Build deep, defend, expand!
Large total conversion mods.
Counted when a user downloads a mod release for the first time. Before Nov 2021 it counted everytime a user clicked the mods download button.
Counted when a user downloads a mod for the first time. Has no data before Dec 2022