Okay, so, it's not a Pokémon. Just a dragon? Hm. The underbelly's outline shading is pretty ugly, unfortunately. It's very bright and seems to represent no depth whatsoever. :l
Wow, that's pretty. And pretty impressive too. If I were you, I would've used less shades, to give more of a Pokémon-y effect, but it's still beautiful. As is it's animation. I'm in love with that fire. o.o Great job on this.
You're right; this is a flawed sprite, unfortunately. The red-eye = evil effect has been done terribly, and it seems as if it's his (presuming it's a boy) whole eye, as opposed to just his iris, as the original intention of whoever it was that first did the red eye = evil effect was (I guess; the iris gives off the evil effect, so I presume so). The hair has very unnoticeable shading, and no-one, realistically, has jet-black hair. Try and refer to sprites such as *pokemonelite2000 image removed* or *pokemonelite2000 image removed* (presuming you're doing the Gen III style of spriting). The Pokéball also lacks shading. :l
Wow, if I didn't know better, I would've thought this was new Pokémon, shape, concept and shading-wise. It could be less monotonous, and in my opinion, the tail's curl should move a bit on the second frame. Speaking of animation, I love the way you animate your sprites; it's just like how Game Freak does it, in Diamond/Pearl.
In my opnion, the Pokémon is pointless, and Aquarigon should be a single-stage Pokémon. From an artistic point of view, this is pretty flawless, however from every other perspective, it's just a filler Pokémon, with hardly any detail and a unmemorable face, as Chesu rightly says is a key factor in creating Pokémon. I'm not a fan of this sprite; sorry.
As I said when critisising (spelling?) Aquaphin, this Pokémon would be far better off as a single-stage, pseudo-legendary Pokémon. Either way, this is truly amazing. I like almost everything about it, the pose, the colouring, the spikes going down it's back, the little spiky shape on the fin, etc. I say "almost eveything" because: a) nothing is 100% perfect, and b) the face, as with it's prevolution, is very unmemorable and unregonizable amongst other Pokémon that you may encounter. That aside, I love this, and, with a few tweaks, this could easily be on my team, if this were to be in Generation Five, as one of my favourite Pokémon (me liking water-types in a plus, too :3).
This looks like it's from the The Dragon Cave adoptable thing. The style is not what I'm used to, so I'm - obviously - not used to critisising pieces of art in this style; for a non-Pokémon, though, it is an appealing sprite, and looks pretty cool.
As with these.
Lileep, much? Even the name sounds like it. But I like this, in general. The flower on it's head needs some centre-aligning, and the root-dress... thing, needs more depth and needs to appear to be resting on the floor, in my opnion. Once again, this doesn't really have much contrast between the shades, which I don't like, and don't think it suits in with the rest of the Pokémon sprites out there. This does resemble more of a Pokémon, though, so kudos on that.
In general, you're a good spriter, so keep at it, and absorb crit like a sponge, and most of all, apply the advice given to you.
Good luck!