JustiNewells has written
"Different Floors"
Since there's the 3D tiles, I think that would be a great idea to make them able to put some over others, and walk over it.
This would allow great, bigger and funny maps, also good remakes.
For get this working without putting 'Jump' function, may have stairs.
When you are in a lower level and have one 'block' over you, the block didn't have to render on the image, so you look everything like an simple map. But the thing must change when you are on the top of a block, all the blocks that are under you must render on a lower level for do the sensation of height.
The shots must continue like they are. So, nobody gets favored for be on an high place that cant be seen and shot to lower-levelered players.
I dont know how hard is to do this, but I think it's ok to share the idea!
Sorry the bad english, I handle spanish mainly.