I am surprised that the greater power resulted in a darker engrave. I would have guessed that the opposite would have ocuured with the laser obliterating more of the coating.
Something that jumped out to my eye, would be to bring the bottom of the ring he is jumping through in front of the dolphin’s tail, it would give the impression of the dolphin jumping through the ring, and give the design a bit more dimension.
Since it’s done, nevermind - it still looks great. Is the color due to the base metal being brass? If that’s the case, I agree with @gmckayca - that higher power would give a different result.