First off, I love this game! The feeling of rotating the globe works really really well and the whole thing feels very fun to play, and when explosions chain and destroy a whole swathe of missiles it's just an amazing feeling.
A thing I kept finding myself wishing for while I was playing was a "select *this* missile" button, like how you can right click to select a specific silo. The left alt key always selects the same missile, and with space you often have to mash dozens of times before you reach the one you want a firing solution for.
Obviously I have no idea how hard this is to implement or if it actually feels good in practice, so take this with a hefty grain of salt.