Bought the bundle of Costume Quest + Grubbins on Ice at the start of the month on PSN, and I really liked both games (although Grubbins was a little bit too short imo, but made up with an interesting ending). The dialogue was funny, the graphics charming and the gameplay rewarding enough.
The slowdowns did make things a little bit annoying here and there though, as well as the transformation playing each time a battle happens, but using the various costumes and battle stamps to find the more fitting ones was nice, although to win against the boss in Grubbins I had to pick a specific setup of costumes and stamps that I didn't exactly like, but oh well.
Being able to pause the game when there are cutscenes to read the bubbles is a nice touch.
All in all, a really cool game. I hope there will be some more of it in the future, especially given the end of Grubbins, although I'd hope for something longer and more variegate than Grubbins was.