-Add the possibility to stack Walls and pillers on top of each other, so that you can build higher rooms.
-Maybe add Ladders, so you dont have to build those big stairs, they should also be stackable.
-Add Night and a Bed, wich you can skip the night in (some sort of hammock maybe). But there should also be some advantages at night, to give a reason to not skip it.
-Add doors so you can build closed rooms
-Maybe add small Island randomly spawning near you sometimes, where you have to swim to, to get more materials or you find researches of new types of structures that you can build after you found a research.
-Add an online coop mode
;D