Creating Levels

I want to create levels in Unity with a bit more complex structure than your average tile based platformer. Look at the mobile game badland. That is similar to what I want to achieve. What is the best way to make levels like that? Do I draw in the entire map, import it into unity, and then add my colliders, or do I draw out all my objects and then place them around the maps? Or is there a better way I am not aware of?

 

Can you describe what you're trying to do in a way other than directing people to download a 6 year old game?

 

Ok. I want to create a world that has bumpy rocks and stuff going in any direction all over the terrain that will be unable to be fit into a tilemap.