Instructions
Make your way to the flag that signifies the midpoint of the level. You will see the second star coin surrounded by blocks.
Jump on one of the Bob-Ombs falling out of the pipe above you to ignite its fuse.
Kick the Bob-Omb against the large blue block blocking the star coin by running into it from the side. The Bob-Omb will explode and blow up the block.
Leap over the pit created by the absence of the block to reach the star coin on the other side. Pass the midpoint flag to save your progress to this point as you continue through the level.