I know this isn't a downloadable game, but Jason Rohrer with Music by Tom Bailey: Diamond Trust of London is a long winded game with a lot of soul. It's a little artistic Nintendo DS game by a real genius of the medium. It also needs money.
$78,715 to be precise. The reason? Well, Jason Rohrer needs to make quite a few copies to comply with Nintendo's just lovely platform requirements, and being an indie, he doesn't have a whole lot of cash lying around.