Just pursuing the idea of the knight sacrifice which I like more and more, I can see a couple of defenses for white, both not all that great. After 15.g4 Nxg4 16. fxg4 Qh4+, white can either block with the queen to keep it in play: 17. Qf2 Qxg4 18. Bxd6 Qxe4+
or move the king: 17. Kd2 Qxg4 18. Bxd6 Bxe4+ with white's rook hanging and the queen out of play.