What's the Most Time You've Spent with a Single Player Game?

Probably Tales of Symphonia at 200+ hours, mostly because I've played it to completion 3 times. The closest to that would probably be Bayonetta 2 at 150+ hours.

I don't want to count Pokemon Y, which I clocked 600+ hours in. Even though most of that time was spent breeding Pokemon, that was primarily done for the multiplayer functions (battling and trading online).
Man, I get the love affair with Nintendo and Zelda.... I honestly do. But BOTW doesn't even crack my top 20 on playtime single player. counting multiple playthroughs, every final fantasy and dragon quest will win that. Even single player, Final Fantasy and Dragon quest and everything Bethesda win out.

I have no doubt Zelda would be up there if it had an achievement system or something but for fucks sake
camping the mount lord as a mount and figuring out there was no way to even keep it was a heart breaker.
Thread inspired me to pick up Skyrim, which I have never touched, even though I loved Morrowind and Oblivion back in the day. I only have a PS4 right now so I got Skyrim SE. Man the graphics are rough, especially after Horizon. Here's to hoping the game has the depth I've been looking for lately, which I honestly felt Horizon lacked. It was pretty and fun enough, but didn't hold my interest beyond the main story and a few side quests.
Very rough estimate: I probably played Captain Tsubasa 2 (on NES or emulated) at least one hour per week since it launched 27 years ago. That would put it into the 1400 hours range.

I love that game. It´s my all-time favorite.
2110 hours 8 min in diablo 3 PC.

Dont have GW 1 installed to check but i guess its more than 1000 hours on that too.

Also in MH2 portable got like 700+ hours on a single character.

EDIT oh shit, you said single player, well MH2 portable was played alone only
220 hours on Dragon's Dogma on PC. That doesn't include the time I played it on the PS3 too when Dark Arisen came out (or it was on Plus or something). I have no idea how long I played it then though...,
According to Xbox, I put in "10d 3h 13m" in on The Witcher 3. Add another 81h 29m for the Gog version (sure to go wayy up when I get around to playing the DLC which I already bought on the PC).

I spent more than 200 hours in Lost Odyssey when I first played it too. I got lost way too often in the Temple of Enlightenment lol, but I'd just keep going there to level up.

I have 150 hours 49 minutes in Breath of the Wild according to my Wii U. I have not much more motivation to play it anymore since I just beat it today.

There's this, but it doesn't really count, because I'll start it and it'll just always be running in the background (even though it uses kinda a lot of my CPU resources...)

It isn't uncommon for my desktop to be on for a week between shutdowns...
I went past 999 hours (the internal clock doesn't count past then) on Pokemon Y and the original Ruby version back in the day. Granted I played those games for like 3 years straight. I have hundreds of hours on each other mainline Pokemon game (barring Sun & Moon) as well.

I've replayed Fire Emblem 7 several times now. I'd say at least 120+ hours on that.

Most recently, I have 75 hours and counting on Breath of the Wild, and I'm nowhere near finished.
Oddly enough, Halo: CE might be my alltime high, just for the campaign. Across the Xbox, PC, emulated 360, Anniversary, and MCC versions... Maybe 200 hours? I've beaten it so many fucking times, replayed every level at least twenty times over.

Skyrim and Witcher 3 must be second and third, 150 hours each.
Either Halo 2, Wolfenstein: Enemy Territory, or Diablo 2. Not sure exactly how long but those were all games that I spent way too much time with back in my peak gaming years.
It's either The Witcher 3 or Persona 4 Golden. I know for a fact I spent close to 80 hrs in P4G, however my play time for Witcher 3 is just fucked on PS4 so I can only assume it's close to 80 hrs.
I think I played 75 hours of Fallout: New Vegas and 50+ hours of GTA V. I'm guessing I spent 40ish hours on Twilight Princess.

Breath of the Wild is probably approaching 100 hours and I've only done 47/120 shrines, 1/4 dungeons, found 94/900 Koroks, located 3/12 memories and I still need to visit four whole regions on the western side of the map (plus explore Eldin, Hyrule Ridge and Akkala in more detail.

I might be playing BotW forever.
Probably FFX.

Took 120+ hours, I think, to do everything, including the Monster Arena. Then playing the remasters and beating all the Dark Aeons and Penance as well as all the monsters... yeah, tons of time spent on that.