Ecco 2: Sentinels of the Universe was a planned sequel to Ecco the Dolphin: Defender of the Future for Dreamcast that got canceled around the time SEGA announced that they would be stopping production on the console and focus on being a third-party developer. Given the fact that the first game was later ported to the Sony Playstation 2 later the same year, it’s not clear why Appaloosa Interactive decided to stop development on the sequel, rather than port it to PlayStation 2 as they did with the first game.

The game was uncovered to the public in 2016 by Hidden Palace, a wiki community dedicated to video game development preservation.

This build comes from a Katana Dreamcast development kit. The discs were included along with the kit. The game features "a few playable level via level select with a complete working debug mode," but there is no music or sound in them.