I like the little bits of his head pushed out when the bullet hits - was that all done in post? I thought in your original you said you added blood so I assume there was already something back there. If so then it all blends quite well together, not overdone at all imo
I gaffer taped a hose pipe to the back of his head (hehe) and used a heavily compressed garden sprayer to blow blood and gunk out of it. His head was obviously left intact. It is a great system, because you can be ready for another take in less than a minute and is very safe.
Then after selecting the best take, I took it into commotion (could use photoshop or any video-paint program) and clone stamped out part of his head for each frame. I then added the extra bits of head flying off and other little details like blood coming out of his nose. The grading hid most of the detail though. Although it is very fast, I still think people register the effect, even the the detail in each frame. They just don't know that they are seeing it.