New Super Mario Bros./World 5-B

Icy courses are a common occurrence in World 5, but the ice formations here are actually quite tame compared to the odd terrain in other stages. With many gaps in the ground, you still have to watch your momentum. Icy slopes give you plenty of opportunities to slide around. Having a Blue Shell here not only lets you clear the course quickly, but also access some neat secrets!

Level walkthrough
Run along the icy ground, jumping over the pits as you approach them. Up a slope and past a Goomba is a Snailicorn. You might not have seen this creature if you skipped World 5-3. They can't be defeated by stomps or fireballs, but you can push them into a pit by jumping on them repeatedly. Using a shell is also a valid method of defeating them. Jump over the next few gaps and defeat the Goombas. As you continue right, you can choose to jump on to the ice platforms up above to reach some coin blocks, but beware the Paratroopas.

Go past the Paratroopas and go up the slope to get to a platform made of ice that extends past the slope, which has three Goombas. Drop down below the ice platform and hit the lone block there to make a 1-Up pop out. Go right and avoid the Paratroopa. You should see a Star Coin below you. After you drop down from the icy platform the Paratroopa is on, go back left to obtain it. Go right and over the slope to pass the checkpoint flag. A Snailicorn guards a single block containing a power-up on the next ice platform.

Jump to the next platform from the one with the Snailicorn. Knock the Koopa here into its shell and kick it forward. It should slide on to some thin ice pillars with more Koopas on them, netting you plenty of points and a 1-Up. The arrangement of ice blocks here leaves many gaps in between, but these one-tile pits are small enough that you can bypass them just by running over it. Jump to the next icy landmass and leap on to the ice platform above the previous area. Hit the P-Switch and run left, making precise jumps over the gaps along the way. At the end of this path is a Star Coin, which would normally by inaccessible due to the brick blocks in the way.

Back on the ice landmass, slide down the slope, defeating some Koopas along the way. You may wish to grab a Koopa shell with you for what's coming up. Jump over the gap and go up the next slope. You should see an opening below that leads to a jagged slope with a Snailicorn. There is a Star Coin behind the Snailicorn, which you can get by patiently hitting the Snailicorn back with jumps until you're far enough to get the coin. Alternatively, if you're holding a Koopa shell, throw it in to knock the Snailicorn out and grab the coin remotely at the same time.

Go back up the slope and continue onward. There are some more slopes here as well as a lone Paratroopa. You can go straight to the right to reach the flagpole. You can also wall jump up the opening in the ceiling where you see two coins. On the ceiling, there are some more slopes you can slide on. Jumping from here to the flagpole lets you achieve a higher score.

Star Coins

 * 1) The Star Coin is plainly visible below an L-shaped ice block formation. You can approach it from both sides, but going right and backtracking to the left is the safer and easier method to get it.
 * 2) Jump on to the ice block ceiling above the section with many Koopas. Press the P-Switch and run across the ceiling quickly, making precise jumps to clear any gaps along the path. Get to the left fast enough and you will be able to nab yourself a Star Coin.
 * 3) The final Star Coin is at the end of a jagged slope guarded jealously by a Snailicorn. Either push it back slowly or just grab a nearby Koopa shell and toss it in to kill the Snailicorn and get the coin.

Alternate exit
You must be Shell Mario to access this hidden exit. Near the end of the level, you can see an opening that you can wall jump up, with two coins hinting you to do so. Keep wall jumping up and over the ceiling and go left. Go into a Shell Dash as you run to the left and stay in your shell to break two brick blocks obstructing a narrow tunnel. At the other end of the tunnel is a warp pipe. Go through it to be taken to the red flagpole.

This alternate exit takes you to the second warp pipe in the world. It lets you skip one or two courses as it leaves you just outside the World 5-Castle.