First and foremost, apart from being a very cute concept and play on words, this is a very well contained illustration that manages to incorporate a lot of colors and imagery without being visually overwhelming. The stylization of the fireworks, moon glow, and dragon/dinosaur scales is an example of using largely the same technique effectively across different applications.

That said, the only elements I feel that sort of works against the piece is the sterile boarder and font choice. The textures in this piece are few, but they, combined with the rendering on the figures and use of gradients in the background elements, are enough to keep it from feeling flat. I think if there was just some minimal rendering or texture on the boarder, it would tie in better with the rest of the piece.

On the font, while I understand the choice for a somewhat whimsical font in keeping with the subject matter, because the piece itself sort of calls back to illustrations from the 1950s-60s, the font feels a little too modern for it.

Overall, it's a wonderful visualization for an often-heard phrase, and a very pleasant piece.