Not sure what the actual term is called, but it's a feature (seen in Shantae: Risky's Revenge) where the player can jump from one layer to the next (with the exception of the background and hud layer). You can see it in action here. I'm not sure if you can do this with a tile map object, but I think that using separate sprites might be better. Now, it might be on a different layer, it might not be. It could be all one layer by using fancy effects and what not. However, personally, I think top layer is invisible and what you see behind the current layer is the bottom one. As you move to the back layers, the current one becomes invisible. As you jump forward, the previous layer becomes the background layer and the top layer becomes the current layer. As far as collision is handled, everything is interacted on the current layer. This all speculation, so I apologize if I'm not making sense. :/ I'm not that good at explaining things.