World 1 is the first world in Super Mario Run.
The world consists of "Up and Over," "Wall-Kicking It Underground," "Paratroopas in Mushroom Valley," and "Bowser's Castle Hangout."
Up and Over
Up and Over consists of Goombas and Slope Slides. This level is a good introduction to slope sliding and vault jumping.
Wall-Kicking It Underground
Wall-Kicking It consists of Slope Slides, Piranha Plants, Goombas, and Bounce Pads. The level is a good introduction to Wall-Kicking.
Paratroopas In Mushroom Valley
The level consists of Paratroopas, Goombas, and Mushroom Platforms. This level is a good introduction to using Paratroopas as platforms.
Bowser's Castle Hangout
This is the first castle you'll encounter. The area consists of Dry Bones, Lava Bubbles, and a False Bowser at the end. The level is a simple guide to Bowser Battles, and when completed, gives you the necessary Toads requiered to get Blue Yoshi and Toadette. Beating the level again gives you 100 coins.