Hello there. Well, sure, why not?
The head looks a little big, I'm unsure if you meant it to be that way, so I'm just saying that if you intended to make it that way, it looks like a little too fat, especially the cheeks (Or those things that juts out if them) could be put a little more to the left. I'm not saying anything on the teeth, because you're obviously not finished with them. The black behind the eye is too big, and the lines that go up to it's forehead are a little too far up, in my opinion, and you could make the lines a little lighter, because they're on a highlighted spot. I know the lines on the official sprite is like that as well, but I think it would look better with lighter lines. The spike and the last rock on it's tail is weirdly propositioned (I don't care if it's like that on the Gold Sprite, revamping is about improving sprites (And having fun, but that's besides the point)) Move it a little to the right so that it's a little more covered. The spike closest to the head on it's underbelly (If it has one, that is) is a little too fat and rounded in my opinion. The outline of the spike to the left of the coloured one looks bent unaturally, as well as the one closest to the tail spike and down.
Back to the head, I noticed that the chin is a little too rounded, and the jaw is too big (Did I mention that before...? I'm just typing here). Oh yeah, the first two spikes that are not coloured and shaded yet are supposed to connect to the same rock (Or body part, whatever), but it doesn't look like they are. More like the left on is bent and too long, and connects to where the previously mentioned rock connects to the one after that. The right one also is too fat. Actually, I noticed quite a lot of the spikes look a little messed up, you better check them and fix them.
And that's that, I guess. Woah, was it that long?