The only part I really really liked was the wrap-up party at the end. Seeing all of the cast (hero and villain) just chilling out while Music Meister played a quiet turn was nice. Even his final message was decent.
The rest of the episode, I got a chuckle out of a few bits (like the toy-costumes and stuff).
And as in his appearance, BatMite gave a nice monologue about the show.... his first appearance using a letter from the writers was a nice touch. This time, I guess it had some similarities to fan feedback.
And Ambug Bug was interesting, I only know of him via the DCUniverse Online game.
But the rest of the episode was a bit on the silly side.