Metroid Prime developer Retro Studios’ mysterious cancelled platformer has been streamed for more than four hours

Fans of Metroid Prime developer Retro Studios are continuing to explore a leaked build of Harmony, the company’s now-cancelled 3D platformer.

Last week, more than four hours of Harmony were streamed by a user with access to the game’s work-in-progress version – and for those watching, it was their best look at the game yet.

Harmony was a linear 3D platformer in development at Retro Studios during the Wii U era, it’s believed. All development stopped prior to the team beginning work on the upcoming Metroid Prime 4.

But while a finished version of Harmony will likely now never see the light of day, an unfinished version continues to pop up online, played by fans keen to showcase what was being worked on.

“This is purely for preservation purposes,” reads a disclaimer by Twitch streamer Stumblyn, who played the leaked build of Harmony and then posted the footage to YouTube. (Other videos showing Harmony gameplay footage have been removed, so it may be this also doesn’t last long.)

Harmony stars a red-headed female hero capable of encouraging nature through the power of song. In one sequence, she can be seen singing to coax out a variety of forest friends, who then join together in song to create a spiny vine you then leap along to progress.

The power of song can also be used to call forth larger animals you can ride and take charge of during combat. One example is a mossy troll character that looks a bit like Sully from Monsters Inc. This chap packs a punch, but can also be used in puzzle solving for picking up large items.

In another sequence, we see the hero riding this forest troll to pick up a large acorn, which she then sings and grows into a large tree for her to climb.

Nintendo, which owns Retro Studios, typically never comments on projects that were cancelled before they were made public.

Retro Studios is now putting the finishing touches on Metroid Prime 4, which is set to launch at some point later in 2025 for Switch and Switch 2.