World 1 takes place in the Mushroom Kingdom. The first level starts in Princess Peach's castle's front yard, but then later on you get farther out there. Larry Koopa is the mini and final boss in this world. There is one mushroom level, in this world, where you have to jump on the mushrooms without falling down or getting hit by enemies. The giant Goombas are the enemy fights in this world. You just have to jump on their heads two times each, and then a treasure chest will appear with toad inside, giving you three super mushrooms.
Tip: If you collect all three star coins in every level and in every world, you will unlock a secret world 9.