Layer 1 stays still with these levels. Layer 2 is the one that's falling. You need to use the "Layer 2 Falls" generator in order to get that effect. Level Mode 08 seems to work the best with this setup. I haven't gotten it to work with both subscreens though, so I don't think you can do that with Layer 2.
Also, be sure to put the screen exit at the screen where Mario is and not where the exit pipe/door is. It'll give you a warning message, but it thinks that Mario's trying to get up to the exit, and not that the exit is coming down to Mario.
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