for what its worth
Okay first off I beat the game on my first try; it took a while but I beat him. The formula to beat dark Yoshi is very simple to figure out and thus effected the score. I realize editing and programming games is difficult however next time try using your own characters.
P.S said formula is using fire until you're health is lower than 1000 ( which is also the strength of most of Yoshis atks) waiting until Yoshi uses meteor or combo then continuing to use fire. Its way to big of a flaw. Im rooting for your next game m8