All Planet Start
Four teams, four planets, four completely separate tech trees.
Every team starts from nothing on its own planet - Nauvis, Vulcanus, Fulgora or Gleba - and must independently research the entire tech tree using only what that planet provides. No shared research, no imports, no help from the others. A team only stops being alone when it researches its planet's discovery technology, which now costs that planet's own science pack. That merges it into a shared unified force which accumulates every discovery so far - and only then does anyone get thrusters and interplanetary travel. Until a planet has been mastered, nobody leaves its orbit.
Play it with friends, one planet each, or solo by hopping between teams and running all four yourself.