I had a little time on my hands and decided I would try to find out what the possible "Highest Score" could be for Fireworks. After about an hour, I came up with an answer of
11,034. I'm not entirely sure how accurate my work was, so it could be off by a lot, haha.
What I did to get this number was simple. I recorded myself playing Fireworks to be able to slowly watch the game and calculate how much you would get after each level. When getting the numbers, I would first count how many were in that level and figured out how many total points were possible.
However, with all of the different random seeds, there would be many different possibilities of what you could end up getting if you had a truly perfect game (There's also the fact that the way I might have put in the bonuses earned could be a little off).
11k seems like too large of a score to be possible, but who knows, it could entirely be possible.
But if someone were to get that score, they would get 2,206 credits.
Anyway, I thought I would share this since it could possibly be around the maximum score possible, haha.