Space Engineers has a 'survival' mode, where you need to scout asteroids and gather ore, refine it, assemble parts, craft, weld, dissasemble/grind. Then you also have NPC spaceships that you can assault, meteors that can hit your base that you need to build defense for and in multiplayer you can make player factions and combat it out with other players. I reckon something similar will be in Medieval Engineers, obviously in medieval times appropriate. But I'm pretty sure the emphasys will be on building.