You did really well on the sub pixeling for the shadows moving to reflect the tail. Which makes it a shame that the flame on the tail is static and your outlines on the tail especially are quite crunchy feeling and not at all smooth. It also increases and decreases in width randomly and the movement animation lacks fluidity.
But like i said, A+ on the lighting.
Yes, you're right about tail - more work (and frames) should go there, but everything that I tried looked as the tail was growing and shirinking so I decied to make more simple animation (movement up and down), and failed aparently
). And the flame was forgotten. Mabye next time I should put more time in animation. Thanks for comment :D