The Tides of Time was the direct sequel to the original Ecco, released in 1994, again developed by Novotrade International. As with Ecco the Dolphin, the Mega-CD version of The Tides of Time featured an alternate soundtrack composed by Spencer Nilsen. The controls for the first game were kept, and The Tides of Time maintained the same level of difficulty as its predecessor. New puzzles were added, such as following another dolphin around and a 'scavenger hunt' of sorts later in the game. One of the additions was the Metaspheres, which could transform Ecco into different animals. The transformations were level-specific, and included a seagull, a jellyfish, a shark, a school of fish, and at one point a Vortex drone. 5 unique pseudo-3D levels were also added to the game. The health meter, the air meter, and the Glyphs returned in The Tides of Time. Both the "charge song" and the "confusion song" upgrades returned from Ecco the Dolphin and were usable from the start of the game.