Created by Boston Dynamics, the mech is called BigDog, a four legged...well, quadruped robot powerd by gasoline engine that drives a hydraulic actuation system. Equided with plenty of sensors, an onboard movement A.I. that keeps it balance while its moving. It had sucessfully "conquered" quite a wide variety of environment: mut, snow, ramp, rocky lands...

There's 3 more of these robots from Boston Dynamics, Read more for their vids. 

{scaa=sony aibo,aibo}

    You get the vids from their site, just click on the respective robots to view their info. and download link (located on the left pane); or from my other server (still in queue, should be fully uploaded by 10AM GMT+8):

All the vids are copyrighted to Boston Dynamics.