Apparently at they last minute they cut out half of the game's content with the plans to release it as a sequel, only this game kind of flopped so the sequel was never released.
One of the guys behind the original game wants to make a sequel, but needs a ton of petition signatures in order to justify its release - http://www.petitionspot.com/petitions/toonstrucktwo/ . More info at http://www.rockpapershotgun.com/2010/08/06/show-tremendous-interes t-in-toonstruck-2/#more-35398