It’s hard to explain specifics—maybe it’s just personal taste—but I feel like the player sprite looks a bit ‘muddy,’ and the flight animation isn’t very clear. Overall, flying also feels overly long to me. The attack animation is interesting, but the exhaled flame looks a little messy too, though it probably fits the art style.
I’d say the main recommendation is to generally improve pixel art skills. Our team’s game also fell a bit short graphically because, well… I was the artist XD