How can I make my stone objects look less shiny? I'm trying to replicate a scene made in UE4 using the same assets, but I'm struggling with the textures a great deal.

In this case, a lot of my objects appear overly shiny rather than looking like they're made of stone, it looks more like plastic.

How can I remove the shine effect almost entirely from these objects?
I am assuming you are using the Blender Game Engine. Try turning down the Specular Intensity on your materials.