An update:
I played some Defender yesterday at the arcade that's about an hour away..
After giving it some thought and fiddling, there are some other aspects of Defender that I may not end up putting into Atlantean, again, mostly for screen-clutter reasons. Defender had a nice big bitmapped screen with tiny-tiny graphics. In console-o-fying it, this advantage is lost unless I do like Defender did on NES and keep the art all tiny and shit, and to be honest, if that were the case, I wouldn't even bother making the game.
The one glaring thing I noticed is this:
Being able to shoot the humanoids. The art is all too big and spritey now. You're likely going to nail the humanoids way too much, especially if you're cruising the surface of the map.
I am going to see how the difficulty is without being able to, and if it feels right, I probably won't add it in. I really do get the feeling that having it in place would make the game un-fun. The humans would be dead sooner than the arcade game since the screen-proportions are way different. Since this is Defender inspired and not a 1:1 clone, I think it will be OK.
The advantage to not doing this means I can make the abduction-setup look cooler. The sprites can overlap. It will look neat.
I understand that shooting the humanoids adds various depths to the game (shoot them all, kill the mutants with the reverse glitch)... and it increases the difficulty since you have to aim good when shooting the Landers...
so, does anyone have any input on this?