One of my favorite games (and there’s many) for the Dreamcast was Seaman. Released in 2000, Seaman still seems revolutionary. You were involved in the entire life cycle of the creature, eventually conversing with it via the Dreamcast’s microphone. Even though Seaman is, to put it gently, an odd life form, you really became attached to him as if he were an actual pet.
In an announcement nobody saw coming, Japanese news outlet Nikkei has said Nintendo plans to bring Seaman to the 3DS. The game would fit perfectly on the console, surely utilizing the 3D, microphone and gyroscope to full effect. I’m skeptical if it will be released in North America, as Seaman 2 never saw a release here, but it’s certainly worth seeking out regardless.