New Super Mario Bros. 2/World 3-Castle

This level features many Grinders, also known as the "spiky saw-blades of death." These will hurt Mario on contact, so be sure to avoid them.

Start by jumping over right to the ? blocks to get a Mushroom or Super Leaf. Continue by jumping from platform to platform when the Grinders are out of the way. After going over a goomba, you will find another area that is patrolled by a grinder. Wait till it passes, then jump over. Use the alcove with coins to avoid getting hurt if necessary. As you cintinue onwards, go up the platforms and hit the ? block on the right for another Super Leaf. Continue going up until you see a Star Coin to your right. You should jump down from as high as possible and keep pushing left to get it. Once you get the star coin, go through the door to the top-left.

On the other side, you will reach the midpoint flag. Jump over the grinders ahead when the time is right and hit the ? blocks for another Super Leaf. Next, you will have to go through an area guarded by many small and a giant Grinder. Do your best to go through without being hit, preferably by staying behind the giant one. On the other side, you will see a star coin guarded by a Dry Bones and two grinders. Wait till the grinders come and go, then jump down onto the Dry Bones. The right ? block has another Super Leaf if you need it.

The next area will force you to jump from platform to platform while being chased by a giant grinder. Go at a fast clip, but don't always jump immediately; you go faster than the grinder when running, and should thus have time to spare. When you reach the boss door, Jump to the far right to reveal a hidden block. Go on top of it and go right in order to reach a bunch of coins, the third star coin, and a ? block containing a Super Leaf. Then go through the door to face the boss.

Boss: Wendy O. Koopa
Wendy fights in two phases. First, she floods the room with water, then sends in Cheep-Cheeps to distract you while she jumps around, hoping that at least one of them will hit you. Underwater, she is invulnerable unless you have a Fire Flower. Soon, the flood will subside, and she will send more Cheep-Cheeps jumping out at you, before jumping some more herself.

The key to this fight is avoiding Wendy during the watery phase, and quickly jumping on her during the dry phase. When she spins about in her shell after being attacked, she is invulnerable but easy to dodge. The Cheep-Cheeps are mostly a distraction to force you to come closer to her, but are easily avoided by swimming at a different altitude. One strategy is to simply swim under Wendy when she jumps, forcing her to go back and forth.