I'm a big fan of nostalgia decks and the creator has done a good job with his artwork. However, I don't see how this won't be an IP issue. Just because you put "Unofficial" in the project title doesn't mean you are in the clear, as far as I know.
Paper Mario wrote:I am in no way affiliated with Nintendo or the Mario IP. This is a fan project
In other words: I didn't bother to pursue a license. I know this project will have zero impact on the Nintendo organization as a whole, but it's still another artist's IP (albeit a huge corporation). The deck is fun but I fear it's doomed....