Great to hear someone's already tried it! Honestly a bit too quick--try the newest build (Near-Final 2) and try beating the final boss without the sweater again ;)
As for pieces, that's one of the parts I need to solidify--there's actually a fifth color of piece I'm not using, because I'm not sure how to balance it. I want to set up a "bag" to balance the piece distribution, but that will be a tomorrow thing probably.