It's very nice, but I can't help thinking that it would have looked better with a gradual variance in tone. What I mean is, you have all of these very dark colors, and then the bright yellow, and the green. While this does make those two things pop, it also mutes the rest of the model, and you have to really look for the rest of the details. One recommendation I would have had would have been to use the green on the pustules on it's left shoulder and the entrails, then gone over it with a thin layer of the color it is now, suggesting that the beast is filled with that green liquid, and at the same time making those details pop a bit better.
Anyway, I have little experience actually painting minis, so I don't know how difficult this would have been to achieve, but those are just my thoughts on it.