Dungeoneer is smartly done and really enjoyable, though an undervalued boardgame on many sites, possibly because it does not come with heaps of pretty toys (read: minis) like so many fantastical fightfests (eg. Zombicide, which I didn't like at all, and Gloomhaven, which I think is pretty good (6.5) but irritating to set up/take down and has a very unfortunate "kill everything" mandate--if I just wanna battle, I'd rather play a strategically deep war game like Advanced Squad Leader or Panzergruppe Guderian). And mechanically, Dungeoneer is quite confrontational between players--there are many clutch "take that!" moments, which may alienate some players who are co-op/solo oriented.
For me Dungeoneer > Gloomhaven, 7th Continent, Gloom of Kilforth, Hand of Doom, Zombicide, Dungeonquest, Talisman, Space Hulk, Lord of the Rings Card Game, One Deck Dungeon, and many others.
Dungeoneer players alternate turns as the dungeonlord/monster hurler so the monster intelligence IS intelligent. For me, this is a BIG part of it's success--the vacillating role of each player as hero and GM and the certain knowledge that the monsters will take advantage of the reckless adventurer.
Generally speaking this is a clever dungeon crawler that focuses on quests, adventuring/exploration, character modification, resource management, and battle. Leveling up occurs quickly, altering playing styles, and during the course of a game (approx. 40-60 minutes for 2 players), characters will explore rooms, escorts prisoners, take skill tests, alter the shape of the dungeon, challenge other players, fight monsters, deal with traps, boost skills, build a pack of monsters, and do many other things.
Like a miniaturized and confrontational variable-map version of the great Runebound (3rd), Dungeoneer gives players more goals and variety and choices than the "kill everything!" hack 'n slash-style fantasy games, and the ultimate experience is a rich adventure, a memorable story, and very exciting (aprrox.) one hour experience, especially when a player embarks upon his/her 3rd quest or runs low on life...
That so much memorable and creative adventure comes in two decks of cards rather than a 20 pound box of stuff is to be applauded.