New Super Mario Bros./World 2-Tower

Bowser Jr. must be quite fond of things that spin, because the tower is full of them. From sets of spinning platforms to rotating blocks of various sizes, you better get used to the constant rotation in order to reach Bowser Jr.'s chamber at the top. Hone your wall jump skills if you wish to take an alternate route up the tower.

Level walkthrough
The most immediate feature you will notice as the level starts is the presence of large spinning wheels with four platforms secured to them. The platforms always remain level, but their position will constantly vary as the wheel spins. The first two spinning wheels are the most risky, since you can fall into the abyss below and lose a life. There is a set of blocks above the second wheel, one of which contains a power-up. Use those blocks to get on the third wheel directly above the second one. Wait for the wheel to carry you to a solid stone corridor before jumping off it.

There is a moderately high stone wall ahead, one that cannot be jumped over. You need to get on to the rope hanging from the ceiling nearby. Once on the rope, move to the left and let go once you clear the wall. After a few bends is another spinning wheel, but these are less dangerous because you won't lose a life if you miss a jump. When the platform you're on moves to the top-left of the wheel, you can jump to a very narrow ledge on the left wall. If you wall jump up here, you will reach a door that takes you to a potentially harder alternate section of the stage. Going through this door will let you get a Star Coin, but note that you won't pass by the checkpoint flag.

Whether you want to go through the door or not, you should head right first, where there is one last spinning wheel and a rope hanging above it. At the end of the rope is a red ring which spawns red coins around the spinning wheel. Jump off the wheel and go right to get a Star Coin. Now, if you want to get the next Star Coin, you should head back to the secret door from before. Otherwise, simply jump off the last spinning wheel once you see an opening in the ceiling and use the spring to reach a green Warp Pipe that will transport you to the next section. You will pass the checkpoint flag shortly after entering this section.

There are some brightly-colored square blocks here. The blocks will rotate from time-to-time, and it is best to jump on them when they're perfectly level. Once you've jumped up to higher ground, bump into the small red block to make more rotating blocks appear. These blocks rotate a short while after the central block rotates, so the timing for jumping across these blocks is a bit harder to grasp. There is also a bed of spikes below that can hurt you if you fall. Jump up the steps, avoiding the Dry Bones as you do. Hit the small red block to make some more rotating blocks appear. These help you to reach the red Warp Pipe, which will take you to the confrontation with Bowser Jr.

If you decide to go through the door, you will face a different challenge. There is a golden N-shaped structure secured onto a rail. You need to wall jump between the two walls of the structure. The whole structure will move once you touch the walls, so keep wall jumping to move along with it. You will soon move over a high ledge, which is when you should fall off. Quickly jump up along thin platforms as the N-shaped block falls back down and jump on the top of the moving structure this time. There will be a gap in the ceiling with the next Star Coin. Jump up to collect it, then keep wall jumping up the next N-shaped structure until you are above a new door. Go through that door to fall to the small red block near the red Warp Pipe.

Even after you've bumped into the small block that generates the rotating blocks necessary to reach the red Warp Pipe, you still have yet to obtain the third Star Coin. It can be visible at the top-left corner of this room, but it is way too high to jump to. Instead, you want to wall jump up the small gap between the red Warp Pipe and the wall to the right of it. You will soon bump into the final small red block barely offscreen, which will create some oddly shaped blocks into the chamber with the Star Coin. The first, triangular block rotates non-stop, while the second rectangular block tips to the side when you stand on it. Use these two blocks to reach the last Star Coin, then return to the red Warp Pipe and go into it. Enter through the double doors to challenge Bowser Jr.

Boss: Bowser Jr.
Bowser Jr. is back, and he hasn't changed his tactics at all. He will still try to run into you, and will throw in the occasional jump. He will also stay in his shell if you stomp him, rendering himself immune to stomps. Again, fireballs and the Shell Dash are effective alternate methods to damage him. The only difference to this fight is the presence of quicksand below the arena. Falling in isn't a death sentence, but it can be difficult to get back on to the main platform.

Star Coins

 * 1) In the alternate path with the N-shaped block structures. Keep wall jumping on the first structure, jump off at its peak then jump on to the top of the structure to reach the coin.
 * 2) At the bottom-right corner next to the last spinning wheel before the Warp Pipe.
 * 3) At the top-left corner of the room with the rotating blocks. Wall jump between the wall and the red Warp Pipe to hit a switch that makes platforms appear so that you can collect it.