Most hours spent on one game?

Hands down Runescape. I can't imagine how many hours.

My proudest accomplishment is around 300 hours on modded Ark Survival Evolved in single player.

I have played well over 800 hours in Destiny 2 on PC. Probably the most hours I've spent in a single game.

i would be crossfire or pubg mobile on of them .
and i still play them :lol:

GTA Online. I have a lot of playing hours there but also in BF4 over 2K

500+ in Team Fortress 2 over years haha. I used to play it a lot.

over 800 hours of overwatch and counting lol.. might sound wild since so many people ive spoken to hate that game now, but i really played it a lot the first year it came out. (still play it when bored so.)

World of Warcraft, since it's been out over a decade and I've been playing it since it came out.

I just checked. I have 6000 hours of time on TF2. Makes sense as I played it non-stop for 5 years straight as my main recreational/competitive game.

600 hours on Pokemon Diamond - rookie numbers compared to most of these posts lol but it was a great time sink on long car rides as a kid