This was a great year for multi-platform games. Exclusives were a bit dry, so many heavy hitters came out of the woodworks, so you were happy with any system you owned.
Red Dead Redemption II
Red Dead was the biggest contender against God of War this year and is a no-brainer for the best Multi-Platform game. The level of detail in this game hasn’t been seen since GTAV and has an unprecedented amount of love put into it. There’s no other game like this out there.
Runner-Ups
Far Cry 5
Assassin’s Creed Odyssey
Monster Hunter: World
Battlefield V
thebinarymessiah.com 
Yep! The fact that I forgot about this game until you made a comment proves that.