Hold Usage
Holds are notes which need to be held down for a specified duration. The most literal usage of holds is when the note being transcribed persists and lingers, but there are countless other creative uses of holds. Rather than thinking of the sound that a held note would be attempting to emulate, one can more generally consider the visual and tactile feeling associated with holding down a note. Effective usage of holds is not only dependent on accurate transcription, but also flow, texture, and visual impact.
Holds can easily be abused and made awkward. For instance, attempting to keep a note on column 2 held down while trying to hit complex fast rhythms on column 1, while may provide an interesting challenge, may be abrasive and heavy when trying to construct a more musically oriented experience. Clearly, effective usage of holds depends specifically on the goals of the chart and the concepts being applied, but it is worth paying attention to hold density given how strongly those holds can impact the feel of a chart.
In KBO, holds visually burst when they reach completion successfully, and this visual mechanic places further emaphsis on another concept that is useful to consider: placement of the end of a hold note. A bunch of hold notes concluding at the same time is enough of a visual indicator that it almost feels like something is happening at that given moment in time. If you are layering hold notes simultaneously, sometimes you want to avoid that artificial visual effect caused by the overlapping of the hold ends, and so staggering the hold ends, even if it is just by a little bit, can help "soften" the effect and allow the hold to feel like it fades out gradually. Lining up the hold end with another note or staggering it off of the notes also has a very different contrast. Try playing around with these different timings to find what works with your goals.
Here are some examples of alternative usage of holds:
Although the long holds on columns 4 and 1 directly transcribe the low bass notes in the piano, the shorter hold notes around them only transcribe the attacks of the piano notes. These piano notes are not held for any significant duration, so the hold part of the notes do not follow these sounds directly. However, these holds are still effective, because they reflect the atmospheric, wipsy string chorus texture.
After the quad hit, there are no more notes in the song being played, but the pulse of the sidechain effect can still be heard on the following downbeats. Without new notes in the song, it may feel a bit awkward and strange to add notes in the chart. The approach taken here is to use the ends of the hold notes (in conjunction with mines) to force the timing of the release of the notes to match the sidechain pulses. Rather than telling the player to push down on a button, they are telling the player to release a button.