Note: The screen presented here is from the Atari 5200 and Atari 800 versions of the game. If you are playing the game on a different system, some of the points mentioned below may not apply.
The Slides introduces slides to the gameplay which you will see again in the later levels. Slides force Bob to fall down in whichever direction the slide goes. But Bob is only forced to fall down the slide if he steps across the very center of the slide. This means Bob can solidify the floor on either side of the slide's center without actually falling down. Approach the slide from one side and walk along the floor up to the center, and then jump to the other side of the slide and approach from the opposite direction. Bob will not die no matter how far down a slide he falls.
With the exception of the island, approach this board by completing it from the bottom to the top, and fall down the slide at the top to complete the island.