I love shrooms, but I have never even played a UT game in my life, I'm a Source mapper and gamer.
It looks pretty sweet from the screen shots though, so good work. I myself am actually making a shroom map for CSS once summer break comes around, this inspires me more to make it. :)
Pros: EVERYTHING!!! From the "toony-ness" to the custom vehicles, EXCELLENT design, a true piece of art work.
Cons: Nothing, cept mabe some more color and a day time version
Improvements: DESU!!! MOAR!!! DESU!!! MOAR!!!