Some comments after 2-3 hours or so:
* I'm hearing (good) music during combat. It would've been nice to have it during the rest of the game, though, especially considering the proportion of time spent outside of battles. Lack of voice isn't a big deal for me.
* The writing alternates in quality between good and really good. It's never amazing, though, which disappoints me considering Tim Schafer's previous output.
* The combat is fast and the special abilities (via stickers) are well-done. It's a bit simplistic so far, but hopefully that'll change. There are no random encounters--this is a good thing. Also, like strategy RPGs, your health goes to max after each battle.
* The pacing is good. There's not much time spent on filler (hitting stuff to collect candy is optional and doesn't make a huge difference) and the robot costume's turbo-speed minimizes travel tedium. The game is generally densely-packed with clever, entertaining stuff.
So far, it's a really good Japanese-style RPG. Worth the $15 if the quality keeps up for another 4 or 5 hours.