Walk to the left and jump over the two gaps ahead. Ride the elevator to the top, jump to the left, head up the next elevator, and go through the door. Walk under the diamond enemy to the left and head up the ascending platforms. Another diamond enemy might be floating by when you approach the elevator ahead so watch out and try not to get knocked off. If you have to, wait just below it until it leaves, and then make a break for the elevator and the door. When you reappear, jump over the diamond enemy and head up the elevator. Once you reach the top, go to the left and then up the elevator ahead. At the top, go into the door and you'll appear at the bottom of the descending platforms.
Farther ahead there will be another elevator. Head up once the diamond enemy passes by. Ignore the door beside you and continue to the left. Wait at the bottom of the ascending platforms for the diamond enemy to pass by and then start going. Stop once you reach the spot where it levels out again and wait for the next diamond enemy to pass you. Once it does, continue upwards. When you reach the platform right above the door, jump over it, and then head up some more until you reach the platform right above the elevator. Wait for the diamond enemy below to go away and then step on the platform. It'll disappear and you can head up to finish the stage.