I enjoyed your game quite a bit.
Some things that could improve the overall experience without taking up additional dev-time (at least in my opinion):
1) Use a more retro font. This all text input is reminding me of old DOS machines and this would catch that aesthetic.
2) The pdf would actually not have been necessary and you could explain it all ingame during the first 3 missions. When reading the pdf it was very confusing to me, but when I used it the first time it was quite intuitive, especially since you show the commands that are allowed.
Overall good job!