Knights of Pen & Paper 2 Deluxiest Edition

For this achievement, you need to finish a dungeon. You'll need to clear a couple for the story so this isn't missable. The first dungeon you'll encounter is called Nearby Cave, which is found during the "Chest of Plenty" quest. Potions are super cheap in this game, so it's a good idea to bring a few. You can't rest in a dungeon, and leaving the dungeon causes any progress made to be lost, and the dungeon will have a different layout when you come back.

In the dungeon, there's a bunch of randomly generated rooms. The rooms can have a trap, enemies, an event that could be good or bad, or nothing at all. When going through a dungeon for the story it's best to simply concentrate on getting through the dungeon as quickly as possible, as you probably won't have enough gold to buy a ton of potions early on, and will run out of energy quickly.

For Nearby Cave, you need to find the stairs to the 2nd floor and then find the room with the boss. Achievement will unlock after you beat the boss and leave.