Believe it or not, this is nowhere near the most difficult thing passed or FFC'd on pad. People have now passed 26s on the ITG scale, and iirc at least one 18 has been quadded. This song wasn't even that difficult at the time the video was shot 7 years ago; both Chris and Matt had probably already quadded it.
He's not unbeatable. He didn't win the last two KACs or the last two Extra Exclusive tournaments. He's taken second in at least one other regional DDR A tourney in California too.