Surprised at all the Horizon posts.... that's awesome. I skipped out on the game because it was releasing right next to Zelda and I still had Nioh and Gravity Rush to play. I should really considering picking up Zero Dawn.
That said, no way does it top my #1 this year: Breath of the Wild. Zelda on Switch (and WiiU) isn't just the best game of the year, it's arguably sitting right next to Bloodborne as the game of the generation. No doubt, it's the best open world game of all time.
But, second place would go to Sonic Mania, for sure. It's incredible, too.
No matter how you slice it, this has been a phenomenal year for games.