DOOM, DOOM II, and DOOM 3 had a surprise release today on Nintendo Switch. For anyone who has rushed off to download them are also in for another surprise. All three games require players to log into the game with a Bethesda.net account. If you do not create an account, you won’t be able to play the games.
If you do create a BNet account, you can then log into the games and play them offline. It does seem a bit odd but I suppose it is to help identify players when they play online.
— Daan Koopman (@NintenDaan) July 26, 2019