Ecco: The Tides of Time was the second game in the Ecco the Dolphin series, a sequel to Ecco the Dolphin for the Sega Genesis, Game Gear, and Sega CD. It continued the story of the first game and featured similar gameplay with a few new additions. There was a sequel planned for Tides to finish the series as a trilogy. This game was scrapped and Sega released a spinoff called Ecco Jr. instead. The series was later brought back on the Dreamcast with an entirely different storyline in Ecco the Dolphin: Defender of the Future.
Trellia's future was a dolphin paradise. The dolphins had evolved helium sacs, and could thus fly; they also displayed limited telekinetic powers. The ocean had developed its own mind, and waterways that floated through the skies (called the Skyway in Tides of Time and reproduced as the Hanging Waters in Defender of the Future) apparently connected all the more normal waters of Earth. There were also a few floating basins of water. Ecco travelled through this future for a while, and found the Asterite.
The Asterite told Ecco that something was amiss. When Ecco used the time machine to save his pod, he split the stream of time in two. One possible future for Earth was this bright, happy future of flying dolphins; the other was a dead, mechanical world, sucked dry by the Vortex. The Asterite itself had been 'killed' in the past by the Vortex Queen; how it was talking to Ecco then wasn't explained until later. The Asterite sent Ecco back to his own time after their conversation.
Back in his own time, Ecco ended up having to piece the Asterite together by bringing the globes that made up the creature back together. The final pair of globes had been taken by the Vortex to their future; thus, Ecco had to get there and retrieve them before the Asterite could help him defeat the Vortex once and for all. The Atlantean time machine was not an option; it could only go into the past. The problem was solved when two Vortex drones captured Ecco and took him to their own future.
The Vortex future was full of strange machines reminiscent of the final levels of Ecco the Dolphin. None of these levels auto-scrolled, however. One of the levels was Gravitor Box, in which gravity was manipulated in unusual ways. Ecco did eventually find the Asterite's last two globes, and once the player beat the boss guarding them, another time portal opened to Ecco's present.
With the Asterite complete again, it was able to bestow Ecco with the same powers as it had last time — breathing underwater and a song that could destroy the Vortex. It also called all of Ecco's fellow Singers to help with the fight against the Vortex. Ecco himself fought the Vortex Queen; however, she again escaped, reverting to a larval state and bolting for the Atlantean time machine. The Asterite told Ecco to destroy the time machine, so that everyone could live in peace. The Vortex Queen, who arrived in ancient Earth after using the time machine, found creatures she could not rule over, and through the eons, the Vortex were forced to simply integrate into the ecosystems of Earth. Ecco, instead of destroying the time machine, uses it and disappears into the Tides of Time.
There was a third game in the series planned that would have continued this storyline, but it was never released. An interview with Annunziata indicates that this third game would have involved Ecco joining the Atlanteans.
This build of Ecco II is approximately 50-60% complete, and contains many never-before-seen or different stages from the final version, as well as unique music, enemy graphics, debug functionality, leftover objects and hidden 'easter eggs'.