This is a controllable gun robot for the Blender Game Engine.
You can download The 3d-File on Blendswap:
http://www.blendswap.com/blends/view/66930
The limbs of the machine recognize the ground, thanks to Python and some floor constraints , it is a simple ragdol that reacts with the ground and transmits it to the armature bones with some helper-empties in the BGE.
speedpaint video: