That phoenix looks pretty cool!

While, in general, you have a pretty nice looking sprite there, for the fire bird, a couple of issues are standing out to me a little. The main one being the varied directions of it's wing and tail flames. Flames usually flicker in a certain direction, either reacting to the wind, or simply flicking upwards in the absence of any other outside forces. As it is right now, it just looks somewhat rough and zig-zag-y. It also doesn't make much sense for there to be any shadowing on the one side of the twist above the tail. The fire is making it's own light, so it won't be affected by normal shadowing rules.

The composition of it's design, however, is nice. I really like how it's body is formed.

This looks highly decent:) I can't wait to see how you animated and programmed this boss. Also, I agree with you about the perfection thing.