Here's a variant I thought of for when you just want to play a 2 player co-op game. Thoughts or suggestions welcome, as I've only had the game a few days, so I may be missing something obviously wrong!
2 players must enter the dungeon, defeat the boss, steal his treasure and make it out alive! Setup is as normal, except 4 random treasure cards are placed under the Boss on the boss tile. Monsters do not roam and during the endgame, Summoner stone/abilities are not used. The rest of the rules are as normal until the boss is defeated - both players must enter the boss tile and each take 2 of the 4 treasure cards - either equipping the treasure or adding it to their loot pile. They do no necessarilly have to enter the boss tile together. Endgame - the 2 characters must now move back to the entrance tile, although every tile that could generate an encounter when it was first placed, automatically does so whenever a character enters it (but only once per tile during the endgame). Treasure no longer appears, although any treasure or encounter cards still on the board from the first half of the game stay on the board and can still be be defeated/claimed - if an encounter is added to a tile that already has an encounter on it, the newest encounter must be defeated first, then the older one immediately after.
Victory conditions - both players must visit the boss tile, collect 2 treasure and then make their way back to the entrance tile alive.
Scoring (if required) - as solo rules
It probably needs tidying up rules-wise, as there are probably holes - eg if one character enters the Boss tile, and the other character is elsewhere - should the character in the dungeon trigger new encounters until he's reached the boss tile and collected his share of the loot?
Any suggestions for improving it and/or making it beneficial to work/stick together?