Initially I thought you're talking about the infamous distortion feedback trick but then Poly D has it implemented too. Re Poly D, you're right it's paraphonic but it really gives the feel of being polyphonic and it's a such a huge change that's missing from the original.
I watched the live transmission to try pick up where the fairy dust goes in to the hardware but couldn't spot one... Doesn't mean there isn't any, could be they want keep hiding it
Haha.. I'm too lazy for that, didn't want to loose a sec here on forum!