osu! is a rhythm game whose basic gameplay is taken from Osu! Tatakae! Ouendan. As in that game, players hit circles, move through slider tracks, and spin wheels in time with the selected music track. A constantly draining health bar can be maintained by successful actions, and the level is failed if the bar ever reaches 0. Playing well also increases the player's final score and letter grade for the level. Levels in this game are called beatmaps, and many of them are created by players.