Osu! (stylized as osu!) is a free-to-play rhythm game primarily developed, published, and created by Dean "peppy" Herbert. Inspired by iNiS' rhythm game Osu! Tatakae! Ouendan, it was written in C# on the .NET Framework, and was released for Microsoft Windows on 16 September 2007. The game has throughout the years been ported to macOS, Linux, Android and iOS. Aside from Osu! Tatakae! Ouendan, the game has been inspired by titles such as Taiko no Tatsujin, Beatmania IIDX, EZ2DJ (EZ2CATCH), Elite Beat Agents, O2Jam, StepMania, and DJMax. All "beatmaps" in the game are community-made through the in-game map editor or through external tools. Four different game modes exist, offering various ways to play a beatmap. These modes can also be combined with optional modifiers, which can increase or decrease the difficulty.