Oh, nice! Looks like you already caught most of my notes, ha.
1. I didn't even get that far, nice catch!
4. I love the idea of planet bonuses, that's a great fix!
I also considered adding the leftover enemy cards to the remaining decks, but I thought it might just drag things out?
Ooh, what if planets have a bonus for the player on one side, and when destroyed, they flip over and have a bonus for the enemies? So instead of moving the leftover enemies to the other decks and making the game take longer, it just boosts the existing enemy decks? Plus it would make a way bigger incentive to protect every planet!
5. Hm, being able to discard unused ammo cards as a way to cycle them does help a bit with having junk ammo cards. That didn't even occur to me.
6. I like the idea of a mint-tin sized game, it would take up way less tablespace than full size cards- I threw mine in full size sleeves, and it's got a fairly large footprint that way.
7. I did, in fact, line both sides of the board with the duplicate zone markers. Not really necessary, but it did slightly enhance the old vertical screen arcade cabinet feel ^_^
I like the idea of a beam weapon option! Also maybe a supermissile that damages adjacent enemies?
You could use the extra cards for the rules- it's fashionable these days to just make everything cards. But it'd also be cool to just add more stuff to the game.
Good notes!