From: BoshStrikesBack | #017
What about Prinny, for the PSP? I know it's not exactly "2D", but I've heard great (terrible) things about it.
Prinny is really, really good, but the final boss is mother****ing stupid hard. I beat every single stage mutation (each stage has different versions of it, so you end up replaying the game many times before you actually get to see everything) and I still can't do the final boss.
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