When the Sega Dreamcast was discontinued two years after its 1999 release, the console still had unfinished business. At the time, the sequel to a game about a bottlenose dolphin named Ecco was in development, according to Ars Technica. Now, a prototype of that game, titled Ecco II: Sentinels of the Universe, has surfaced on the internet after 15 years on the game preservationist site Hidden Palace.

According to Hidden Palace, a number of items related to the original version of the game appeared on eBay in 2008, including several rare compact discs of development materials, prototype builds, and source codes for the Ecco game series. Among them was a disc labeled Ecco 2 that contained the files for the unfinished sequel, dated February 19, 2001.

Hidden Palace has since made the game (which has no audio) playable with the use of a Dreamcast emulator, and an anonymous contributor to the site has produced a file that can be burned to a disc and played in an actual Dreamcast console. Preview the game in the video above.

[h/t Ars Technica]

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