Also want to mention Paratrooper - https://archive.org/details/msdos_Paratrooper_1982
https://retro365.blog/2021/04/07/bits-from-my-personal-colle...
It's interesting how much depth you get out of the additional mechanics, unsurprising the game itself was copied a great deal but coming up with engaging twists on seemingly trivial gameplay seems to have been a lot harder to replicate consistently.