For clarity: I use the first version of the animation files posted in this thread. And it's probably all open doors, but for clarities sake I'll write anyway.

I did notice some oddities that, with a bit of planning could be worked around.

For now, I use one background per file / animation sequence. (so, one .ora file has one sequence only)

The regular MyPaint layer is used as background / scenery and stays editable.

The first of the animation cells is static. What I draw in there stays. But after that, I sequence my moving objects one by one and that does seem to work.

Oddities: After deleting a cell some cells are no longer editable. Work around: Don't delete frames and simply use the 24 given when you first start a file. If you add frames and your last cell is filled with an image, that last frame will move postition to become once again the last frame. So, I only add a frame after an empty one.

Naturally I'd like to be able to use more than one background per sequence, so I don't need to start a new file.

Also: How do I export this animation?

Save as well as export don't allow mpg/mpeg.