I see. so the map/layer which it fades throught would have lots of semi transparent tiles? Interesting idea. Is it possible to make the player swich to a new sprite on a different layer?
Yes, there is a project called LAyers.zip in
http://gamedevprj.sourceforge.net/files/It uses a script, but that is only because there was an error in an earlier version of gamedev and this script worked around it. If you are using GameDev 1.4.5, you can delete the script file and change the 2 special functions like this:
GoDown: Change this function's effect to be "Switch to a new sprite", select "BottomPlayer" as the sprite, and check the boxes for "Retail old state", "New instance", and "Delete old sprite".
GoUp: Do the same thing, except select "TopPlayer" as the sprite.
Then you will see how to switch layers without any script. You should be able to go above and below the grated floor by using the stairs.