your AA is kind of overdone in some parts, making them fuzzy where the reference was sharper. Since it's such a large pic I guess it doesn't matter too much, but it'll cause you problems when you move to smaller things.
My advice for when you start your next digimon, is to pick a completely different lightsource from the reference. Trying to copy pixel for pixel isn't going to help you improve. You aren't going to learn anything about drawing shadows, anatomy, picking colours, and a ton of other stuff. The only thing you're likely to pick up will be pixel art specific tehcniques like AA and selout, which are useless without the others. Also try to add on to the reference. Since digimon's shadows are simplified for animation, try to do things like adding more shades. The main thing is to get as far away form the reference as you can, so that the only thing you're relying on it is for the details like the tatoos or to look at the anatomy if you're having trouble imagining the light source from a different angle..
