Its launch got off to a rocky start, but Mario Kart Tour is now available worldwide on mobile devices. Sensor Tower has already gotten its first insight into how the game is currently doing. According to Sensor Tower, the game is currently the “#1 free iPhone app in 58 markets. This includes the United States and Japan. In the United States, it is also currently #19 for iPhone app revenue. In comparison, Dr. Mario World debuted at #503 on its first day of availability. That said, Mario Kart Tour did better than Dr. Mario World, but there’s a problem. Mario Kart has been a major success on the Switch, becoming the Switch’s best seller, but even Mario Kart was not enough for Nintendo to dethrone the strong start of Fire Emblem Heroes. The game charted at #17 for top iPhone revenue app on its first day of availability, back in February 2017.