Executive assault 2 gameplay. Deemo is a Rhythm Game developed for Android and iOS devices by Rayark, the same developer behind the rhythm games Cytus and VOEZ.Essentially, Deemo is a column-free touchscreen version of beatmania, with an emphasis on piano notes.Currently, there are more than sixty songs available to play in three difficulties for each song, distributed over twelve collections. Deemo M2U ☆Magnolia, Myosotis, Marigold (Violin Cover).