People are going to focus on the pass rush. That's always been the way to beat Peyton, but that's a mistake. Yes, it was good, and forced errors, but Peyton still had time to complete a record number of passes. Far more problematic was that the Seattle linebackers and safeties were "right there!" over and over again. Was the YAC for Denver actually negative? Sure looked that way.
Give some credit to Jack del Rio -- his defensive game plan against the 'Hawks was pretty solid. Lynch was held to under 40 yards, and although Wilson's 123+ PR sounds impressive, he didn't pass all that much. He actually should have been better, but his receivers let him down several times with drops.
Seattle came to play. Denver simply did not look like they did. Whatever the reason, an impressive victory.
The only reason Peyton completed a record number of passes is because after they went up 36 zip the Seattle defense ratcheted it down, they switch to a “nothing deep nothing cheep” defense that basically tell the other team “you can have all the 3 yard completions in the middle of the field you want, but no fast scores or out of bounds clock stoppage”. You can see that in how he only got 280 yards for all those receptions.