Is It Possible to Complete the Nightmare Playthrough the First Time?
Its 100% possible, although it requires knowing the game.
A couple of things worth noting for a playthrough though:
- The old man sect is the strongest by itself but locks you into it. The other sects are weaker in terms of benefits but you can do a ton of them for some insane boosts.
- While bosses do grow stronger its not a huge worry as they grow stronger in levels and eventually cap out, although some bosses will require you to prepare as they can be hard.
- On nightmare all bosses are beatable even if you let it get to day 600 aslong as you get other benefits.