The middle poses is definitely my favourite, it makes me laugh! Not sure why, I just find it appealing.
I would agree with Alerane's suggestion, and make his chest on the upper left a bit more in line with his body, but that is the only thing I can see that needs fixing. On the whole, I really like what you've done here, the poses really seem to suit him being an angry, mocking villain!
I guess I just see the good, no matter what in a minotaur. I refuse to believe they are all evil, mean, etc. If you have a chance, watch Jim Henson's The Storyteller, The Greek Myths, The Story of Theseus and the MInotaur. I guess even Jim Henson himself felt something for the bull headed beast.
Yeah, I was hesitant about doing another bull-type character as a villain just because I didn't want to be repetitive. I was originally going to do a cerberus-type villain, but in the end this design turned out better so i went with it.