Right now it's basically just a simple "survive for X days" type mission (which is easy once you have a base and enough food). Then the other is endless mode - that just lets you play in a single world for as long as you want.
You need to put ice into the water tank to fill it up. Each ice will give you 30 water, and it takes 60-90 water in the tank to grow a plant (It looks to me like the greenhouse gets built with about 30 water already inside).
Are the JSON files like resource_tiles.json and items.json read at runtime?
I tried setting the nuclear fuel to require 9 rad ore, and tried changing the plant biomes to make the terrain more diverse, but that didn't seem to have any effect even on a new game.
