What is MUGEN you ask?
It's a game engine where you download a bunch of characters and stages, but them together in a game and play or watch something happen.
As you would expect, Klonoa has been made for mugen!http://mugen.wikia.com/wiki/Klonoa
In fact, he was made twice.
However, despite Klonoa being in MUGEN, the series doesn't get much love outside that. we don't have any stages for Klonoa (which I have been chasing after for t) and no other characters are playable.