Early footage of the game showed The Hand boss having destructable tombstones in the arena which are not present in the retail release. The Hand also had a different death animation.

The characters are all influenced by kendo martial arts since it was a big part of Takashi Okazaki's (characters designer) life.

Since speed and challenge were prioritized above all else, the team created a heavily stylized setting so the unrealistic animations had a heavier impact when playing.

The game's designer, Emeric Thoa, strove to make the bosses stand out, using games such as Metal Gear Solid and Punch-Out! as inspiration for their visuals and mechanics.

The game was originally titled "Duels."

The early names for the jailers in the game's conception phase had been changed.

The Chain used to be The Law
The Strap used to be The Nemesis
The Line used to be The Wise
The Hand used to be The Father
The Song used to be The Wing
The Burst used to be The Maze
The Edge used to be The Challenger
The Beat used to be The Horn