Once you get a star, you can go to the room upstairs to the right. Enter the door. Inside you will find a room with three glass paintings (two in the DS version). Jump in the one to your right.
There are two stars in this level:
- At the bottom of the slide.
- Awarded if Mario finishes the slide in less than 21.0 seconds. This star will appear in front of the previous one.
At the beginning, turn around and hit a blue coin block, so, if you complete the course, you will gain a 1-up once you return to the castle when your coins are counted.
To complete the slide in under 21 seconds, make sure to hug all of the corners. Do your best to never slow down by not hitting any walls.
There is a trick to completing the slide in even less time. When you reach the first corner, bump into the wall to turn yourself backwards (there is a coin that you can aim for to do this effectively). Note that it will take practice to do this properly. Now that you are sliding backward, bump into the railing on the right side as the walls end to bounce toward the left side of the slide. Immediately jump off of the left side and kick just as you reach the bottom of the slide level. It is possible to complete this slide in under 15 seconds (TAS is 12.3).