Favorite Underrated Games/Hidden Gems in Retro Consoles

I love the classics, but I REALLY love the feeling of discovering something that feels a little more hidden or delving down someone's absolute favorite game that they don't get to talk about with many people.

I don't have many to throw in the discussion, Lost Kingdom 2 for Gamecube is unique and I don't hear it get brought up /too/ often. What are your hidden gems? :o