Ecco: The Tides of Time is the sequel to 1992's Ecco the Dolphin. Players guide the dolphin through treacherous waters while using sonar to help navigate. Various enemies such as jellyfish, sharks, and sea worms threaten to injure Ecco, so you must carefully swim to avoid contact with them. You'll also have to keep an eye on Ecco's air meter as you'll have to travel up to the surface or find submerged bubbles to replenish his breath. The game involves puzzle-solving as well, since there may be enemies or obstacles that cannot be overcome unless you first figure out the solution.