Its a shame that the development for this game had to stop but I’ll share it anyway since it entertained me for so long. The main site is no longer available for details so i’ll try my best to explain.(It was in Korean anyway)
If your familiar with Beat Mania or Percussion Freaks or Keyboard freaks or any other game in the same vien then this game should be easy to pick up. You press keys that correspond to one of 7 notes according to the makers that scroll down. These markers are the ‘notes’ for one(or many) of the instruments in the given song.
The songs are converted from midi format so you can actually make your own songs using their file converter or download pre-made songs. All files can be found here but be warned its a huge page and the words are in Chinese. Just look for the orange text in English that says VOS 1.0 for the main game or VosCreator for the file maker. The rest are pre-made songs.