Paper Mario Sticker Star - The level design is pretty hit-and-miss and some of the logic leaps they expect you to make on sticker puzzles are nutsy. On the other hand, when the level design hits the mark, it leads to glorious things like the haunted mansion in 4-3 and 4-5's minecart ride. And then, there's the excellent base gameplay. Sometimes, this game can be infuriating unless you have no qualms with FAQing the shit out of it due to expecting you to -explore- the levels (I pretty much could imagine, say, Ciato shrieking in rage and slamming the 3DS towards the nearest wall on 5-1). On the other hand, I really like the exploration aspect and the levels are both short and oddly imaginative given the engine restraints on them.
I have no idea how objectively -good- I consider the game to be, but it's one of the funnest experiences I've had in general gaming in a couple years at least. I kinda regret putting it off for a full year out of laziness (I bought this pretty much on release). I really oughta play the rest of the series after I beat this, and I definitely see myself coming back to Sticker Star in and out of itself - it lends itself really well to weird challenges and oddball style changes, not to mention knowing how the game and stages work speed up the game immensely. I haven't tried over half of the Thing stickers, for starters.