That might be covered in the next update. However, there is this trick I came up with in my game.
I started with a background that looked something like this:
Then I told the game to replace each tile used for "shocked Keeby" with a solid green tile when the scene started. Then I could put it back to the way it was when I was ready to show "shocked Keeby" again. Of course, I could have achieved this same effect using sprites, but I did it this way to make room for more sprites to appear in a row together. It ended up looking like this in the VRAM:
with shocked Keeby: 
without shocked Keeby: 
Maybe you could try something like that if you've got enough VRAM space.