Soon after you reach the ? Blocks at Point 1, the moving walls slow down. Stand on the Blocks and look for the ledge near the upper-left corner of your screen—the first Star Coin is located on that platform.
When the walls move back to the left, wall jump up to the ledge and grab the Star Coin. As you do, the platform below you vanishes. Drop to the floor and avoid the nearby Boo until the walls force you out of the area.
To reach the secret exit, you must leave through the door at Point 2. As you approach this area, wall jump up to the ledge.
When you reach Point 3, draw the Boo up toward the Red Ring. Just before the enemy reaches you, jump up to trigger the Red Ring, then collect each of the red coins as they appear.
When you reach the ? Blocks near Point 4, wall jump up toward the ceiling to find the second Star Coin. Grab the Star Coin and drop to floor before you’re pinned against the platforms to the right.
To collect the third Star Coin, you must move very quickly. After you hit the P Switch at Point 5, follow the blue coins as they lead you to the right and up a series of platforms.
Rather than collecting every blue coin, focus on climbing the platforms. As you approach the end of the trail, a Springboard drops down from the ceiling. Jump to the ledge on your left, then dash to the Star Coin before it disappears behind the wall.
If you managed to catch the Springboard when it fell, use it to reach a hidden room near Point 6. Bounce up to the gap in the ceiling, then wall jump up to find another door. Soon after you enter the secret room, the walls begin closing in. Grab as many coins as you can, but make sure you climb to safety before you’re crushed!