COD and halo 3 literally brought competitive shooters to the mainstream
I never played Minecraft and honestly if it wasn't for me looking up it's reception in sales, I would've thought it was a niche game. To me it feels like Fortnite is bigger. This leads me to this other realization, some gamers due to their friends/whereabouts may perceive certain titles to be bigger or smaller than they really are. Like a gamer who plays games like Rainbow Six or COD on Xbox may be oblivious to the success of other big games because "nobody I know" is playing it.2.5 Billion breh.
The most influential game is easily Minecraft. I'm stuck on a teams meeting now so I can expound here and now
This is the highest selling game of all time. Did it in less than a decade too. This game has merchandise galore attached to it. Bedding, clothing, toys with a movie in the works. It has a custom deck of Uno cards. There was enough of a market to create a cookbook based on the game. There is now Minecraft: Education Edition for school aged children to use in school. If we are talking about gameplay and copying it, it might be Dark Souls. I'm not saying that Minecraft is a powerhouse as far as gameplay as I don't believe that it is. It is basically Legos put into a videogame but when it comes to influential nature? Worldwide? This touches the world more than any other game before it. There are college courses based on the game. There is a large contingent of people that make parody versions of popular songs in the vein on Minecraft on Youtube and then those parody songs get more views than the legit song.
Everything that I just stated, all fact, came from a game. No other game is anywhere close. I don't play the game but I'm not going to be contrarian and deny the obvious though.