seems the game has a delayed input from one note to another. Therefore, when you press double keys at the same time it only registers as one key at times. Very frustrating.
Nardeko you don't understand. The lag is there becuase in all games, the arrow should be in the MIDDLE of the line during the beat, which would allow slight deviations before and after the beat. This one has the top of the arrow on the line, such that pressing it too earlly would not register but pressing it far too late would.
good game but a couple of improvements.
1) fix the lag so that the game is actually a rhythm game and not a reaction game.
2) once you do that, make it more difficult (rhythm wise), include halfbeats etc.