I have 600h in the game. 80h in my first game, 260h in my bad attempt at a megabase, 25h in a 100% achievements world, and a few random maps. I haven't even tried doing a deathworld yet.

Then once you think you are done, then there are the mods. I have 123h in one overhaul modpack, enough to technically beat it but not truly scale up. There are several other similar scale modpacks, and there exists a certain hardcore modpack that people say takes 1000h or more to beat.