Here is an overview of the game, via its Steam page:
You are a Guardian of Harmony–a musical genius transported to the world of Symphonia by the Composers to battle the forces of Discord. Together with up to four other players, you will fight your way through the corrupted Timbrelands of Symphonia, eradicating the Discordians and restoring Harmony to the environment.
Discover the Power of Music
Unlock powerful musical abilities and mix and match thousands of unique gear and weapon combinations as one of five characters–Melody, Jaxon, Lydia, Brite, or Ky–as you fight to protect Symphonia, and uncover the secret origin of music itself!
Watch the trailer below. View the screenshots at the gallery.