Per my steam library:

Factorio: 3,375.4 hours

Dyson Sphere Program: 2,505.9 h

Stellaris: 2,236.6 h

Terraria 2,629.9h

Skyrim: 1,239.5 h

Dungeon Defenders only has 600 hours on Steam, but I’m well over 2000 hours between Steam and PS3/4

I’ve also got a few thousand hours in Just Cause 2&3, as well as several Gran Turismo games and Forza Motorsport games. Morrowind probably has 2-3000 hours, oh and I’m not allowed near Sid Meier’s Alpha Centauri anymore.

Secret of Mana and Chrono Trigger are probably up there as well since I’ll replay them every decade or so.

Second Life.