Lovely smooth animation and great artwork!
I honestly do not wish to criticize you, since I'm not as good as you are.
But I noticed something in the beginning of the animation.
For a split second there, when Luigi was saying "Yahhooo!", his head was 3 heads as he was drawing it back.
It's either you were trying to do a "squash and stretch", or it's something you missed.
Whatever the reason was, you're still great! Favorited, and congrats on front page m8!