Awesome cover. The reason why the moon looks toothy, though, I think, is because of the upward-curves under his eyes. The moon looks attentive, and ferocious, as if to pounce upon some prey, which is good in its own right. In Majora's Mask, the moon has the same frown, except without the curves under the eyes. The moon looks angry, but not about to pounce; it's more passively (rather than actively) ominous, I guess.
Anyway, I'm excited about this project. I wish I had musical or artistic talent to contribute...