I'm sorry to say, even though I do quite enjoy the game's inside jokes, charecters and storyline. It gets repetitive and boring after a while not being able to find someone to play online co-op mode, this will only work as a one-time-game with no replayablity (if you're soloing)
NOTE: BEFORE YOU BUY THIS, this game's defination of "multiplayer" is local, that means you need another usb keyboard or controller for another player.
The playstyle is a very generic dungeon crawl, that requires additional players to be fun. although dedicated fans of adventure time will enjoy this, it can get boring after a while if you're soloing through the dungeon floors, grinding 1 gold per golddrops (and also not being able to find people to play with, especially on the PC platform).
Without online co-op on a steam PC platform, the DLC doesn't really mean anything either. (unless you love the show, and like collecting DLCs and everything about adventure time).
I would not recommend buying this game (unless you have other friends with controllers you could plug into your PC monitor to play on.)
EDIT: after playing hammerwatch, playing adventure time does not even feel like it could compare as a game, all this game contains is humor, the grind ratio is unbalanced; loot to enemies ratio is about 1:5, and enemies are sparse, (not enough for a dungeon crawl game), now, hammerwatch is only $10.99 (not including holiday sales or discount.) comparing to this game's price which is $43.99, the price difference is extreme, and makes this game unworthy to dedicate upon.
If you check on the majority of the positive reviews, most of them are done upon impulses provided no solid fact of pros and cons on the game, also with the completetion of achievement (unlockable through progressing through levels and finsihing the game), you can tell people stopped playing before even getting past half the game.
I would not recommend spending around $60 to buy this game and the DLCs, unless you're a fan and in a younger age group, you will definatly not enjoy this game.