I like colors and shading, but if you'd asked me what would make picture better, I'd said that proportions could be tuned. For instance, paws may be shorter. And his left forearm/firearm/his left hand (troubles with english) looks more like his leg, while his right looks okay. Wings may be better to shift several pixels to the back. Dinosaur reconstructions and photos of lizards, as well as their pixelart equivalents, may be used as guide.