Courtesy - Super Hexagon features a medley between the song Courtesy from the game Super Hexagon and a remixed version of the song Bad Apple!! made by Masayoshi Minoshima.
The original Bad Apple!! song was created by ZUN for the Touhou Series game Lotus Land Story.
The mashup has been made by the soundcloud user RedScreen (formerly AlexMashup).
The key notes of the Meet the Flintstones theme can be heard at the near of ending.