Badman 2 demo coming out on the PSN today.
March 2010 release
$30 for the UMD. The UMD will contain the original game as a bonus.
$20 for the PSN version. The original game got a permanent price drop to $10 recently so if you want, you could buy both for $30 or just buy whichever one you want.
A lot more content than the original. In addition to a lot more levels, heroes, and monsters, there are also special monster mutations & a sandbox mode.
I liked what I played of the original game's demo, but didn't buy the game when it was originally on sale. Now that it's permanently cheaper, I might pick it up or I might just wait for the sequel; I haven't decided yet.