I played the original and loved it, but I haven't seen anything about a sequel. I think it was done by the same developer as "Vampireville", and both games are 20+ chapters. If there is a sequel, I'd buy it without hesitation.
"Vampireville" was hilarious, and I particularly got a kick out of the butler. I picked it up when it was first released and have replayed it more than once. The humor is along the same lines as "Mushroom Age", so neither game should be taken seriously.
I replayed "Mushroom Age" a few weeks ago, and enjoyed it just as much the second time around. The cast of characters are a riot and you can't help but smile while playing.