Put the most hours in?

Gmod with around 4,5k hours :D

3294 hrs in CS:GO ;D

SAMP.... About.. 10 years... D:

I have 700+ hours in ArmA 3. Its pretty fun :D

I've put 8.7k hours into Rust

Counter-strike: Global offensive... 1832 hours )

i have 30000 hours with my right hand

I have the most on gmod. Hours:3316

1.4k hours in gmod, and above 2k hours in cs 1.6 non-steam.

I have about 700~ Hours on Arma 3. The game is a really fun strategy simulator of military combat. You can really do some cool stuff with mods, like adding HALO vehicles and weapons :D