I'll tell you guys what happened at the end
In Big's rage over the death of Jade he killed the sparrow. This caused him to earn some bad karma of his own. While meditating he spawned another version of himself, one who chose to continue in his life of rage, as well as the version of himself who went to HongKong.
The AngryBig stayed in the mountain and ended up killing the cop chick when he saw her as a way of paying her back for the evil that he saw her do in her past life. The guy she saw pop out of the bushes was Sun Ko, he didnt kill her. He ran away, but while she was looking for him AngryBig caught her and killed her. It was his punishment that he killed her, as well as hers.
MainBig chose a better lifestyle (although not a perfect one) and was absolved of his sin of killing the sparrow (to a point). His punishment was losing the cop chick.
What I dont understand is how he got so skinny at the end? Was he wearing a body suit through the whole movie? Cuz it did look like it sometimes (because of the odd wrinkles). But he had such motion and the muscles seemed to move under the "skin" and even his head looked wider, so I thought it might be real. Or was it maybe a different actor at the end who looked like him?