Relatively nice sprite, Flygon. Here's some crit, though, to help you improve it. For one, the whiskers that are in front of the face are barely visible at all. Perhaps bringing some contrast between the two colours (and shades) would help?
Furthermore, it seems there is a lotta black outline, even where it shouldn't be - for example, the fluffy tail doesn't look fluffy at the moment (the only reason I assume it's supposed to be fluffy is the shape, and the fact that you said it's a rabbit. Oh, and it looks to have been pillow shaded (the darkest shade on the outside, and it gradually gets lighter as it comes closer to the centre; don't do it). I know that some of Drifloon's sprites contradict this, but I think some coloured outlines, especially there, would be of exceptional assistance. =D
The eyes seem pretty boring and it looks half asleep (I'm not sure, is this intentional?) and the leaves are a pretty lame way of conveying the grass type. Speaking of which, the two on the back not only do not look connected to the back, but also are too thin to have that vein being added in, if I'm honest. Additionally, they lack black outlines which doesn't look good.
On a whole, the palette is nice (barring the whisker Isshu issue). The shading, on the other hand, seems slightly rough and, for want of a better word, dodgy. Try curving it out a little (especially the shading towards the rear of the sprite).
Last crit I have is regarding the two paws/legs furthest away from us; they are far too dark. Use the darkest shade, maybe, but not the outline's shade. Still, it's not a terrible sprite. Good work. :D
And where are the buck teeth?
