I really enjoyed the NPCs in Below Zero but I’d love having more interactions with them. Maybe some sort of fetch quest system, bringing a specific mineral or fish to a scientist maybe, also having to ensure a stable supply of food that the colonists can access. Some NPCs could even be assigned to certain tasks like tending grow beds or collecting water, similar to games like Aska or Fallout 4. It would be fun to balance settlements too, like a farm settlement in a safer biome and a power plant in the deep hot caves. Maybe reprinting colonists requires a certain amount of power + biomass to discourage reckless death/reprinting. Your first one could literally be a biobed that ran out of resources to print and needs you to deliver the raw biomass.