Today, a Hong Kong Youtube channel has managed to get their hands on a copy of the game a week early. They have put up a video showing the first 20 minutes of the game. It’s in Traditional Chinese but should be self-explanatory.
UPDATE – Intro video leaked courtesy of Brandon:
Filtrado video de Pokémon Let's Go, Pikachu! (no contiene spoilers) pic.twitter.com/vzbaTZCAPj
— Centro Pokémon LEAKS (@CentroLeaks) November 10, 2018