[Dungeoneer] Winning

Do you win when you reach level 4th, or when you complete 3 quests?

Complete 3 Quests to win.

In the basic game, completing 3 quests = you win. This has the effect of promoting you to level 4, so it's the same I suppose. But if someone somehow lost a level and then completed their 3rd quest, they'd still win. It's mentioned twice in the rules.

When you add in epic and legendary sets, the game ends when someone hits the highest possible level and the winner is whoever got the most victory points by completing quests.