the...marvellous art of Sapphire? god...
well, it might just be because you play so much pokemon, but let me tell you that art is far from being something to admire, that art can ONLY be seen as marvellous compared to the poor threatment Pokemon has had before that, really.....there's tons of much much better graphics in many many other pixeled games.
your stuff looks good for what you were trying to do, I can see a minor error here and there, but it's mostly good at what it was trying to achieve, you did learn the redeeming aspect of their art which is to cleverly depict very solid volume with just a few shades.
The one place where I think you really missed the Sapphire style, was with the little human, but I wouldnt get very worked up about that, since I think if anything your character has too much vividness and personality to be a sapphire sprite.
I think you need to stop trying to imitate these guys, or you'll pick up all of their bad habits and start replicating them as if they were a necesity for you to do pixel art.
I'll mention the error that bugs me the most, it's with the spikral, now, the highlight at the botton ring of his shell has a very very odd sort of crescent moon shape to it, which doesnt mach the tire-like shape that the shell ring has, you should have the lightest highlight shade cut off right by the middle of the "tire" and extend that darker highlight shade you have for AAing a little bit more than your usual 1-pixel with, to smooth it out.
the koraleon's whole wing area although interestingly shaded is very very confusing, I think it is because you have both wings so close to eachother, so you might want to enlarge the picture and move his left wing to his left, or diferentiate that one's shading from the other by removing the highlights, or applying them in a very different manner.
spiddle now that I look at him looks quite odd, you might have something going on with that cute little face peeking out of the botton, but the lineart is very very weird, it looks like it might topple and fall at any moment, the two little paws dont look like they belong to him since they're mostly fixed to face the camera, rather than oriented to emerge from the center of the creature, and the "slot" from which the head comes out looks like it's just one or two pixels too far to his left to be facing us that directly.
except for spiddle All of them have a very good sense of action, and their poses depict each of them very well, I specially like the way you can just picture the way spikral would paddle out of the field of view if the frame was un-frozen.
now, for the actual designs of the pokemon, koraleon looks a bit like a stealth lugia, kittal like every anime seal ever drawn with a few feathers here and there, spiddle and spikral are closer to something truly new, but I really like sakuramon, since it has that classic feel of the first batch of pokemon, unlike most of the latter which look too aerodynamic to be adorable quirky little monsters, and is quite a bit odd and unique, specially that bald spot over her head.
if you really think there's something very good about sapphire's art that we are still not seeing, show us what it is and why you like it so much, we can tell you how to achieve it if it really is something to admire, and just the act of explaining it to us may also give you a renewed view on their art.