Godfall, the forthcoming fantasy "looter-slasher" from Counterplay Games and Gearbox, will be playable in co-op or solo—but either way you'll need to be online. This was confirmed by the official Twitter account, who said, "Godfall is not a service game, but does require an internet connection to play."
Presumably it's to prevent cheating, so that when you jump into a game with other players you know they haven't done a Diablo 2 and given themselves max stats and all the best items. Keeping character progression and loot drops server-side would prevent that from happening. Although since Godfall won't have PvP, what's the harm?
Godfall will be out on November 12, exclusive to the Epic Games Store.