If this is your first set of missions, then NICE. It wasn't particularly difficult, but it gave me a challenge. A few things you may want to fix, though.
-Cutscenes aren't very believable. Try changing some of the wording in it. Instead of 'I am', try "I'm". The characters seemed a little... drunk.
-In part 3, the generator 4's shield would not come off. I had to find a way to dig into the concrete and destroy it >_<
-In part 1, where you have to open the first door... I managed to unlock it, but an invisible barrier kept me from going. Reloading fixed the problem, but idk if it'll happen again.
Other than this, nice campaign. Had fun playing it