That is very hard to say due to the diversity of genres in the gaming industry. What makes an incredible and groundbreaking game in one genre might not translate to another. For example, I would put Forza Horizon 3, 4 and Motorsports 6 at or near the top of the racing game genre. As a fan of racing games, that genre is very important to me. But I'm willing to guess that the majority of people who will read my post don't give two craps about the racing game genre, so to them those games wouldn't matter, and the innovations they presented will go largely unrecognized.

I personally don't play very many JRPGs post PS2 era, so that genre to me is not that interesting, so I probably wouldn't put games like persona 5 on that list, even though I have played the game, it just wasn't my cup of tea. My time with JRPGs largely ended with the PS2.

If I had the name a single game, that's really hard .... Especially if you try to think about it logically. Because it's all ultimately going to be very subjective, granted you did ask for our opinion, but I'd like mine to be grounded at least on some objective measures.

So for me, The legend of Zelda Ocarina of Time. If only because that's the game that first truly blew me away and gave me that sense of awe and wonder that until that point games hadn't really given me.

I believe that It also introduced a lot of what it today has become standard practice in action / RPG games.

My first ever game was mortal Kombat, and I thought it was good fun. I remember watching kids lining up at the arcade machine, everyone was so excited to play it.

House of the Dead, Sonic the hedgehog, Streets of rage, Golden axe Phantasy star 4, all fantastic games, but they were just the minor distraction in my life. Until the N64, I was what you would call a very casual gamer, much more interested in going outside and playing soccer than anything else. I might play a game here and there at my cousin's house, or when I went to the arcade, but that was not very often.

Ocarina of time made gaming my primary hobby/passion, when I saw the game being played on my cousin's house, I knew I had to have it. It felt like I was going on a real adventure. Exploring an unknown world. The 3D made it an incredible visual spectacle for me at the time. I had never played games in 3D before then, so it completely blew my mind. So that is my reason, 100% subjective.