I will say the original A500 version has a particular charm that's akin to Mario Bros on the NES. So I well understand someone preferring that if they have fond memories of it. The background art is so beautiful, so it's definitely nice to see it there too. But I added the switch so you can always turn it off. (There are other improvements and fixes in this edition that make the game fully compatible with fast machines, for starters!)
The Amiga can change the bitplane data and colours as each horizontal line of the screen is drawn. That's how AmigaOS achieves that effect of multiple windows being drawn "in front" of each other - what you're really seeing is a lot of Copper instructions to change the bitplanes and colours as each of those windows is displayed.
That doesn't, however, mean that one window could have holes/transparency in it to display what's underneath, because the hardware can't work that way.
EHB/bitplane 6 trick doesn't really work for Addams Family on OCS. Dual playfield (which I assume is what you're referring to) is limited to 8+8 colours on OCS. That would be fine for the backgrounds but way too restrictive for the foreground.
Hey, nice to hear from you! I compromised and apply a stipple to the sprite instead, so it has a sort-of transparency which isn't the full hiding effect but removes the need for sprite priority, which as you note doesn't work if the backgrounds are in play.
