Most hours spent on one game?

Probably would be LoL with like 2k hours ;_;

I used to love mass effect a ton so I spent like 800+ in the me3 multiplayer playing with my girlfriend and nephew

It's just an estimation, but a couple 100 hours both on Diablo 2 and on the Fallout 2. I thought about myself as a big gamer (in my time) until I've read the posts of others about 1000s of hours. Oh my gosh...

Assetto corsa, about 800+
And sa:MP about 3000+++

I've been roleplaying since I discovered Grand Theft Auto V FiveM 3000+

Call of Duty Black Ops 2600 , 11 )

Over the years it got to be Wow or Leagues, not even close with the rest.

i spent 86 hours on gmod

servers and mods are still fun

I spent about 2300 Hours in CS:GO since about 2014.

Probably CSS with arround 6000 hours lol