Super Mario Run is broken up into three main gaming modes: World Tour, Toad Rally, and Kingdom Building.
World Tour mode comes with six worlds, each offering four levels. There's also a boss at the end of each world you must beat. When you beat each level, the next level appears until you play through all of them and rescue Princess Peach. As you play, you'll notice pink coins throughout the level. If you collect all five pink coins from a level, you master the ‘easy' difficulty for that level. You'll then be able to play and collect five purple coins, which makes you a master of the ‘medium' difficulty for that level. Lastly, there are black coins. When you collect all five black coins, you've officially completed a level in the tour to its fullest.
The goal in World Tour mode is not only to play through all of the levels and rescue Princess Peach, but to play through all of the levels collecting the coins. If you collect all 120 pink, purple, or black coins from each level, you'll receive a pipe that's the same color as the corresponding coin. When placed within your Kingdom, having a pipe allows you to play another hidden level.