In this video, I cover the introductory cutscene and the initial visit to "The Snoring Tree" that occur before starting the game proper.
It's not evident at the moment, but if you come back to The Snoring Tree later, you can change costumes and interact with the Bubble Dreamer to have him comment on your current attire.
In this video, I show the Bubble Dreamer's comments for every single costume (in order of increasing Electoon requirement).
Note: Whenever the Dreamer says "Sorry, that's all I can remember!", it effectively means that there is no more unique commentary for that costume.
If you're wondering why I didn't use more costumes during this waklthrough, this video should imply why. I like the Teensie characters, but I don't think nearly all of the alternative costumes should've been Teensies instead of a more diverse cast of protagonists and antagonists. It's like if a Mario game overemphasized the role of Toads.