The music game O2Jam judges note hits into four:
The judgment of whether a note is hit or not is based on the distance of the note from the target bar. The descriptions in the following sections apply only to hi-speed X1; in other hi-speeds, the target bar virtually resizes also that much, however the visible target bar does not change. For example, in X4, imagine that the target bar resizes vertically upward to four times its size.
A cool is registered when at least 80% of the note hit the red target bar.
A good is registered when at least 50% but less than 80% of the note hit the target bar.
A miss is registered when the note missed the red target bar. A miss breaks a combo.
The red target bar is the guide to hitting the notes.