After defeating Vortex and returning home with his family, Ecco resumed his happy-go-lucky life in the open ocean, but little did he know what was in store for him. In Ecco: The Tides of Time, Vortex has returned and has started another assault on the creatures of the sea. Now, it's up to Ecco and Trellia, a dolphin from the future, to once again stand (or swim) up to the powers of evil and put a stop to Vortex once and for all. Through 40 levels of deep-sea exploration, you'll have your hands full as you face challenging puzzles and various creatures of the deep. But this time you have the ability to temporarily morph into another animal that will let you get past certain obstacles you otherwise couldn't get around. You'll be able to change into a ferocious shark, take to the skies as a seagull, or avoid danger all together as a jellyfish. Once again, it's up to Ecco to save the Earth from pending doom.
--from review of Ecco 2: Tides of Time at RottenTomatoes.com