No revenue estimate for GOG — its rating/review counts don't calibrate to sales the way Steam's do. The Steam version is estimated at $1.2M — a different platform, not this one.

Wandersong

A musical adventure where you use singing to save the world! Play as a silly bard who embarks on a globe-trotting journey to learn about the mysterious Earthsong, said to be able to prevent the universe’s imminent end. Along the way there’s a huge cast of characters to meet, puzzles to solve and songs to sing! In Wandersong you're a walking musical instrument, and you use song to interact with everything. Different things respond to your music in different ways, so it's up to you to sing your songs, unlock the world's secrets and make new friends! Mac release coming soon!