I think the "build stuff to defend from monsters" is pretty overrated in Terraria/Minecraft, since it only takes a few seconds to dig a hole and be perfectly safe. If monsters constantly tried to break your base like in Factorio, that would be exceedingly frustrating since breaking 1 block is usually enough to stop an entire production line. Full auto production lines are usually quite fragile in Roody:2d.
The monsters in the trailer act more like skeleton spawners in Minecraft where once you find one, you just use it to harvest materials.
For most players, going through the tech tree seems to be enough of a motivation. You "win" by getting to the end of it, and "lose" by giving up.
If you want to play the standalone puzzle version of this game, check out Infinifactory.