Ok, so this is another humanoid, and it looks like a girl. What's more interesting here though are the legs, and specifically the knees. Most humanoids walk and stand with a characteristic bent knee configuration. The bending of the knees allows vertical forces to be absorbed or applied in the absence of a flexible spine, but on this robot the knees look almost straight whilst standing - much more like a human.

Yes, I agree... I watched this clip several times as the walking motion is much more human like than previous efforts and very impressive. I concluded that the robot does use similar techniques to other humanoids - the ZMP algorithm, but perhaps they have tweaked it to be less noticeable. The side on views in some of the other clips of this robot still show the characteristic bent knee.

The google translation of the press release doesn't say for sure what the technical differences are but it does say they measured dimensions and "whole body locomotion" in a real human female and based the movement on the measurements. Here's an excerpt:

"Walking behavior and body work is working to help the human body works and walking with measured MOSHONKYAPUCHA, HRP control technology by applying a two-legged robot has been developed in an operation that is very close to human that."

"MOSHONKYAPUCHA" is the name of a Japanese 3D motion capture system. Sounds like the stuff video game developers use where they put you in a black suit with white ping pong balls attached at all the joints. Might be interesting to compare the HRP-C4 to the previous HRP humanoids to see the differences