So I made a crappy Unfallen concept after the contest ended and figured I'd share this garbage anyway. Basically, clearly; concept is trees; and more trees generally mean higher tech. For example the combat tree there (top left) shoots pods of whatever is appropriate at the enemy i.e. poison, needles, explosives, whatever. The civilian trees, next clockwise are more anthropomorphic being relatable to humanoid (or not) beings and generally more capable of manipulating things. The spaceships are scales of mature trees growing around tech and engines. For example, small ship is a tree or a few trees that grow around engines and related tech with specialized solar panel leaves (blue leaves) to create power. Like their ground based counterparts, they use biological based warfare. Basically, bigger ships = more trees with the biggest being called 'the grove'. Anyway, enjoy, or don't...they aren't very good drawings. 

Sorry, occured to me there are no blue leaves on biggest ship.