Wonderful sense of motion, great silhouette on both of them, charming and successful color palette, and a good proportional scope of environmental backgrounds used.
As much emphasis on shading and lighting that's used on both of the characters, including underlighting Scorbunny with the flame as a lightsource, the only details that are distracting to me are her hat and her mouth. The hat looks kind of gelatinous and shiny, which isn't bad- the effects used are great, I'm just not sure if it applies to the fabric that hat is supposed to be. And the inside of her mouth is one solid color, which only stands out because of the contrast of the amazing attention to detail on lighting and shadows everywhere else.
I understand these could be stylistic choices though, so that's not deductive in any way that I'm voting, because I love the piece. It's cute, and I love the motion in the poses. It gives off a really cheerful vibe, and it's got an optimistic and charming warmth to it that's deserving of high praise.