Build your base on a platform that warps from planet to planet and escape biters before they overwhelm you.
Large total conversion mods.
Augmented or new ways of transporting materials - belts, inserters, pipes!
New ways to deal with enemies, be it attack or defense.
Changes to enemies or entirely new enemies to deal with.
Map generation and terrain modification.
Changes to power production and distribution.
I've started getting big asteroids, but haven't even got rocket turrets yet. Is this supposed to happen? Aquilo is still locked
Asteroids are controlled by evolution. So if you have big enemies as well, then it is supposed to happen.