New Super Mario Bros./World 6-Tower

Bowser Jr.'s tower design is only going to get more fiendish. You've probably encountered Skewers in the World 3 Castle, but flip them 90 degrees and they suddenly become much more threatening. With horizontal Skewers installed on every level of the tower, you can be sure you'll be scrambling to find a safe spot to stay in.

Level walkthrough
Up above from where you start is the first Skewer of the course. This tower is centered on these deadly obstacles, but they can be avoided if you're quick and observant. Like in many levels, patience pays off here, as rushing ahead will likely cause you to get cornered by a Skewer. Get on the two blocks to ensure you're safe from the first Skewer, then go left to approach the next Skewer. You must run to the right in the path of the Skewer, then quickly jump to safety.

For the third Skewer, look for a low spot in the ground for you to duck in, as you likely won't have enough time to get to safety while running from the Skewer. Jump to the left while the Skewer is receding. Get on the thin platform and wait for the fourth Skewer to fully retract. Run to the left to grab the first Star Coin, then immediately duck into the spot below to avoid the incoming Skewer. Jump on to the thin platform and time your jump for the fifth Skewer, as this one moves slightly faster. It doesn't extend very far, so you're safe once you're past the X blocks.

Jumping on to the thin platform after the fifth Skewer will cause the checkpoint flag to activate. Avoid the giant Dry Bones above and keep climbing until you get on to one of three blocks. Wait for the trio of Skewers above to fully reset their positions, then quickly jump to a platform with a spring before they slam across the screen in quick succession. Time your jump from the spring to avoid the two colliding Skewers overhead. Avoid a large Dry Bones and one more Skewer to get to a door. The boss door can be seen above, but you still have some climbing to do before you get there.

Through the door, you will end up in a room with five Skewers that shoot across the screen one after another. Wait until they're fully retracted, then start jumping up each platform as quickly as you can. Try grabbing the Star Coin as you near the top. Jump to the platform by the door to avoid the onslaught of Skewers below. Go through the door to get transported back to the first section, this time on the ceiling next to the double doors.

For the last Star Coin, you should have a Mini Mushroom in reserve. Turn Mini here, then jump off the wandering Dry Bones as it walks to the right end of the ledge. Move to the right wall, then start wall jumping between the two walls until you reach the ledge above the double doors. Go in the pipe here to reach a room lined with spikes and filled with Skewers. Wait until the Skewers are fully retracted, then jump to the middle platform and wait for the Skewers to finish their next cycle. Now, jump to the platform with the Star Coin and fall to the pipe to return to the previous room. Go through the double doors to initiate the boss fight.

Boss: Bowser Jr.
Bowser Jr. fights you at the top of the tower once again, but he has been pretty creative at coming up with new arenas. For this battle, you're fighting on a metal disk suspended from the ceiling, with a bed of spikes below. The disk will tilt in the direction you're standing on, increasing your chances of falling in. Bowser Jr.'s tactics remain unchanged as he still rushes at you blindly. Stomp him three times or toss a bunch of fireballs to defeat him.

Star Coins

 * 1) At the fourth Skewer, go to the very left to grab the Star Coin. Duck in the dent below it to avoid the Skewer.
 * 2) The Star Coin is slightly out of the way while climbing up to the second door. Watch out for the Skewers as you go collect it.
 * 3) Get a Mini Mushroom and use it outside the boss door. As the Dry Bones gets to the right end of the ledge, jump off of it and to the right wall. Start wall jumping up on to another ledge, then take the warp pipe there upward. Patiently wait for the Skewers to retract, then jump to the middle platform. Wait for the Skewers to retract again before jumping to the Star Coin, then fall back to the pipe.