Really cool result. Very impressive.
I am curious about how the screens are being rendered. Are their several bitmaps on top of each other?
Not quite. I keep an array for each slot in the sky - each can essentially have one of 2 values (empty or occupied) - although there is a special case for saved paratroopers. There are 3 logical columns and each column is cycled through in turn. All of the bitmaps for each slot are pre-defined, and then simply displayed (or not) depending on the state of the sky array.
I've finished the code now so will post it soon - it's pretty basic stuff.
@Schmidtn - I'm sitting here at my parents right now - in front of me I have Donkey Kong (dual screen), Parachute, Fire, Popeye and Turtle Bridge. I think Fire might be next. These games formed a special part of my childhood too, so breathing new life to them is both fun and emotionally fulfilling. I also have a Galaxy Invader 1000 console that still works - it might make a nice clone as well.
I need to get a few more Hackvisions!