Yeah and the better is so easy to use , even a beginner wit some knowledge about low poly character polygons flow, can create easily the low poly version.

You have just tu draw polygon on surface.
Try Coat3D for example and it's retopology tool to see whaat can be done and how easy.

For levels, yeah you can create rocks, or walls textures with normal maps and specular, you have just to create a square to bake normal map.

For Coat 3D (i bought it recently) , at atsrting , you have some choice, like semaless textures : you can paint on diff,spec and normal map seamllesly.
You have tool to draw ellipsoid, linear forms , or to increase /decrease,soften normal map volume on the texture:
so you see directly when painting how will it look at final.