Due to the popularity of Mario, Naka wanted Sonic to take over the American market. Sonic's default speed was set to that of Mario while running. Tests were run using the Genesis' tool library, and problems such as flickering, slow frame rates, and shaky animation soon became apparent. Increasing Sonic's speed caused animation problems. Naka solved this by developing an algorithm retained fluidity. All that was left was to optimize of the game speed to adhere to the staff's expectations. The team noticed that different people had different perceptions of the game's speed: some believed it was too fast, which caused disagreements. As a result, it was slowed down.