Pretty underwhelming as a standalone release; it took me less than an hour to beat all of the bosses. If you treat it as an expansion to the original game, though, it's worth the money, since it's basically just another island's worth of content.

Probably harder than the original but it's been like five years so it's hard to compare. Like the original, the bosses are all a cavalcade of visual garbage and unfair ganks, but there's nothing too bad once you learn to parse what's actually happening.