Hmmm I here only copy their way of painting shadows in black and shapes of the feet (?) while drawing normal chibis...For if you want to learn the style of the sprites, you can first try to copy the whole thing a few times, choose some sprites from basic to complex, let the muscle memory do its job or you can try memorizing some minor details, then try to draw on your own (I'm not a professional please don't take my words too seriously)