As we can see, they programed the fight stupid...He should use Geyser at the beginning of the fight so that if Frog gets low on HP, he'll probably keel over before he gets to cast Frog Squash (though he shouldn't know that by then anyways, but it's a New Game+ ending, so w/e...)...& after Frog cast Water he should have immediately put up a Water barrier.
Maybe it's not the end, but just the last we're let to hear.
