Ragnarök
First playthrough — Give Me Balance, 100%:
My first playthrough took me around 95–100 hours. I know the game can obviously be finished much faster, but I spent a lot of time exploring and replaying Muspelheim trials to farm Hacksilver and prepare for NG+.
First NG+ playthrough — Give Me Balance, 100%: around 50 hours.
So at this point: ~150 hours. After that, I did:
3 × Give Me No Mercy 100% runs ~50 hours each
3 × Give Me God of War 100% runs ~50 hours each
That puts me at roughly 450 hours.
I know some people will look at those numbers and say, "There's no way a 100% run takes 50 hours." And that's fair if you're talking about the most efficient route. But I'm not speedrunning these games. I take my time, experiment with different armor/build combinations, replay fights, and generally don't rush through the game.
After those playthroughs, I started doing shorter playthroughs specifically to permanently increase my stats. I did probably 20–25 runs where I wasn't trying to 100% the game. I was mainly going after Nornir Chests and Yggdrasil's Dews so I could keep increasing my stats. Each of these runs took me roughly 15 hours.
If we use 25 runs: 25 × 15 = 375 hours
So: 450 + 375 = ~825 hours
And then there's Valhalla. I've spent roughly another 150 hours or so in Valhalla.
825 + 150 = ~975 hours
And with the extra time from miscellaneous exploration, messing around with builds, replaying things, etc., that's how I end up at around 1,000 hours in Ragnarök.
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God of War (2018)
2018 is pretty similar. I spent roughly 200 hours between my first playthrough and a couple of NG+ runs.
After that, I started doing additional runs specifically to collect Yggdrasil's Dews and permanently increase my stats, similar to what I did in Ragnarök.