Most hours spent on one game?

left 4 dead, I think between 1 and 2, I played 1000+ hours

Wow I feel like a newbie. Most hours I have on a game is like 96 and that is on Sacred 2 for the xbox 360.

I spend over 12 hours in one day in playing GTA5 :D

I've got 4500k Hours on Gmod, been playing it for years+ it was mostly the loading times :(

Clash of clans a few hours every day for the last 5 years.

mines counter strike source with 4k+ hrs of gameplay

On PS4:

Rocket League about 1k
Destiny over 3k

PC:

Rocket League reaching 2k

But as i'm addicted to RL there is no other significant Game in my Library *hehe*

Maybe Ring of Elysium with about 600

The most amount of hours I have spent is on Garry's Mod. I have been playing for around 5-6 months and have already racked up around 2.3k hours.

CSGO, LoL and maybe Mobile Royale.
Even though I spent hella time on WC3.

Probably now it's World of Warcraft, though I tore up the browser games when I was younger. Adventure Quest, anyone?