Red51 wanted to playfully toy around with a 'fantasy' biome whenever the game was considered complete. Shall be sweet if & when he does this for the fun of it, not seriously.
- Build buildings using blueprints is something I suggested hoping he'll poke with once we get NPC Traders. They would grab from the chests to then piece your structure together, somehow.,
- Build cities? I do hope so. 'Millionaire' mod for Minecraft would be a good example on how to do it while making use of NPC Traders. This could once again be poked with on the fantasy biome side of things when the game is complete, and etc. I would expect small tribal outposts first, then villages & towns. Self-sufficient may be difficult, yet light farming I could see. Fishing.
- World government? That may be pushing things a bit far, yet might be neat of you do it in a gimmicky way by having a city hall built to then place rules the AI itself follows with some joke rules. Some 'RPG' immersion type things could be listed & noted within the game.
- Marriage + have kids is pushing the idea way too far now. It would be more proper for mods, or for the likes of 'Stardew Valley'.
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Not bad, I guess. NPC villages is something that 'Might' come, after traveling merchants & NPC Traders. One thing I really do hope is for natural NPC Traders to recruit from the wild to place in your builds with them also being able to tend to their own hunger & food. Be neat if you assigned them their own chests, and where they can gather food & water from. Even having one as your 'traveling companion' also.