My choice would be either Dark Souls 3 or Elden Ring.
Which game would you choose?
Probably something like harvest moon. Long play time with a lot of options to change the games course.
I would pick up an online game I previously abandoned like Dead by Daylight or R6S. I don’t think ANY singleplayer game can keep you entertained for 365 days 24/7. Also 8760 hours of gameplay is enough to make me a god in any online game.
Tetris Effect
That’s awkward moment when you start thinking about op’s question and you realize you’re already doing the thing
Dota 2
Warframe
Skyrim. Or peak Halo 5.
I hate this game but if must play repeatedly it has to be fifa. RPG games would just end.
Damn too easy Baldurs Gate 3 Platinum/All achievements all platforms or Legend of Zelda TotK or get the Platinum on Aliens Isolation for my single player picks. For multiplayer Baldurs Gate 3
Returnal
The Lord of the Rings: Gollum
Minecraft or cyberpunk 2077
ROCK AND STONE!
Elder Scrolls Online. I haven’t played it much the past 2 years because I would rather play through single player games. But if I can only play one game, that would keep me entertained as I play through the content from the last 2.5 years.
I don’t really play any other MMOs or online games. I suppose another option would be a strategy game. I haven’t really touched Civ 6, but I spent a lot of time on the previous 3 games, especially 4 and 5.
DayZ
it probably has to be an online muiltiplayer. I hate multiplayers, but 1 full year? only multiplayer games can bring enough fresh content (in terms of players you meet) to go on that long