To be honest, I don't really understand the opposition to a Knytt stage, since the world of Knytt can certainly be violent at times. Plus, it would make an absolutely beautiful stage.
But yes, I think using Knytt as a punching bag is out of the question. I believe that comment was intended as a joke.
I agree to what has been said, but the punching bag, made me think of something else...of adding more content to the game..making it more than just a "brawler".
For instance, there was a very good idea about creating some sort of mini-game collection of indie characters; i think this is a very good idea, and very feasible to do and integrate into I.B..
Considering we *should* have a whole bunch of character sprites, that could make a whole bunch of actions, it shouldnt be too hard to create a couple of mini games involving the characters...say in order to gain/aquire an in-game currency, wich can be exchanged for say, new characters, music, "trophies"*, etc.
Replay value in the sense of motivation of new content is something that i think is lacking (generally speaking, tho obviously not applyable to every case) in indie-freeware games, and this could be something really fun to push the experience.
What's more, and returning to the original idea, it could become one big "tribute" to indie gaming; Say, by collecting money, you can unlock "trophies" (or whatever you want to call it) and see the original story behind the character, games featured, and info about the original creator.
A 1/multi player sidescrolling beat em up, would be fun as hell too.