- No two hitobjects can be placed on the same tick This includes hit circles, starts and ends of sliders, and starts and ends of spinners. osu!mania maps are exempt from this.
- There must not be any obscene imagery in the background/storyboard/video content. This includes nudity, near-nudity, sexual references, violence, drug abuse, etc. Keep things PG, suitable for ages 12+. Images should be on a level that can be displayed on all-audience TV, on public signage, and of nature that does not require censoring in any country.
- There must not be any unused files or 0-byte files in the map's folder. 0-byte files prevent other files in a map's folder from properly uploading. An automatically generated .osb file and storyboard .thumb files are the only exceptions.
- Do not edit the
.osufile to modify difficulty settings or insert break times in ways that are unintended for each respective game mode. Other.osufile edits such as stack leniency, slider velocity, skinning settings, etc are acceptable.
- Letterboxing and countdown options should be consistent between difficulties of a mapset.
- Slider tick rate should not be modified through the
.osufile. Most custom values result in unsnapped slider ticks, however tick rates 0.5, 1.333, and 1.5 have practical use and can be applied only when they fit a song more appropriately than standard tick rates. - Kiai should start on a sound in the music. Doing so otherwise causes the kiai flash to feel unrelated to the song.