The song "Horatio" has two unique Challenge Charts depending on the version.

In the North American PlayStation 2 version, Shock Arrows are used more frequently and before 16th notes, forcing the player to occasionally step in the center to maintain the stream patterns.

This was changed in the arcade release of X, reducing the quantity of Shock Arrows in the beginning and end and spacing them out further. This modified chart is also used in the Japanese console release of the game.