Notice how his mask has started to gain more thicker lines. Each time he fights with his mask on he improves his skills and becomes stronger. But it also closes the boundary between Shinigami and Hollow. The classic example of yin and yang, black and white, good or bad, that we see in stories. Ichigo is in a way becoming 'bleached' and so becomes a mixture of both of these making him a character of both sides of the coin.
Right this was pure gold. Also notice how his mask actually splits in half when he screams or what appears to be roaring. That's new also and could indicate his Hollow growing more powerful as well.
We actually might see another Ichigo vs. Hichigo during the fight against Uliq, I expect something similar to what happened with Zangetzu and Ichigo when he first fought Kenpachi in the SS Arc.