One of the first levels with buzz saws. If you activate every one of the platforms it will make it much easier to recover if you take a fall.
The level is much easier if you have a cape and if you use the top platform.
Try flying underneath the real exit with a blue yoshi or a mario with cape you will find another exit which will lead to a secret underwater level called Soda Lake.
HINT: Use regular yoshi, drop below the normal exit and at the very last second jump off of him, he will fall but you will jump above a platform and find yourself behind the real exit.