Elevation

[AHappyMuffalo]

We should be able to build on multiple levels, like make a second floor to a building, build on top of hills and build upwards in mountains.

Players build ladders which allow colonists to get up to higher floors, players go up and down floors by pressing the Home and End keys or pressing up and down facing arrows in the bottom right of the screen.

[JimmyAgnt007]

No, this is Z-level stuff and its on the frequent suggestion list for a reason.  It would require a fundamental alteration of the engine, a whole heap more logic programming, and months and months of effort.  Please search topics before posting, Tynan has commented on this before and dozens of threads have been made asking for it.  Its not a new idea.