I started playing this too (just beat the HS area), and my one big problem is the performance too, like Mr. Slime Appears. The load times are bad, the game stutters like hell on a new area load, and I've had 2 lockups already and one graphical glitch where the map was colored blue. Also I'm not a fan of all the collecta-thoning... a lot of the quests seem to be "find these flags", "find the Chinpokomon", "fight these bums"... the game's a lot like how I'd expect a Ubisoft take on Paper Mario to be.
It's a great love letter to the show though, tons of little in jokes and references of obscure minutia.