Legendary Starfy is actually the fifth title in the Legendary Starfy line, but is the first version to be released for Western markets. It is a platformer, but usually takes place underwater, changing the dynamics from the standard gravity physics one usually expects in such games. The protagonist is a hyper-cute, silent protagonist starfish, the eponymous Starfy, prince of the heavenly seas, who interacts with other characters in dialog and cutscenes, trying to figure out why a rabbit in an environmental suit named Bunston has crashed into his home. He is pursued by the Terrible Trio, a squad of pirates bent on capturing the rabbit. Starfy's journey takes him far and wide in search of the bunny, and the truth!
Like several Mario platformers, Starfy gains powers via suits that he finds throughout the various levels. The flying ghost, which can whomp on enemies with a powerful spirit blast and get past obstacles with the after-effects, as well as pass through certain barriers; the stunning chicken, which can create stepping stones out of stunned enemies and unleash a very loud cluck which nukes enemies in a radius; the precisely-swimming seal, which has a knife-swim attack that can also break through certain kinds of ice; and the fire-breathing dragon, which you can use to burn away obstacles and victims.
The star orbs you collect throughout the game serve both as health regeneration items and can be used as currency to buy items for your character. When damaged you lose a portion of your heart meter, but unlike in other such games, no loss in power results. Until you lose all your hearts in the meter, you attack at full power. Exploration is a lot more laid back than in other platformers as well, allowing time to explore and get past obstacles in a similar manner to some Metroidvania titles. The enemies are also fairly sedate by platformer standards.
A second player with a DS can actually connect to your DS to play during certain portions of the game, mainly boss battles (where you play as Starly, Starfy's sister) and other small portions of the game, including a dress-up mode.