Great episode. Sure it calls back to a lot of continuity, but I managed to catch most of it. Seeing all those references to decade-old episodes was hilarious. Specially the return of Mr. Hat. That caught me off-guard.
As for part 2. My theory is that, since they already did a Terrence & Phillip episode, (Cartman's Mom...) and a Terrence & Phillip fake-out (Cartoon Wars), my best guess is that they'll try something different, but still surprise us. Double fake-out, maybe?