After the free main chapter, here's a tl;dr of the rest of the plot:
Main female protagonist is appointed commander. Sets up base. Alien base is found and promptly destroyed. End.
Not overly complex, but a nice slice in the life of an X-Com commander. It's the plot in between that fleshes it out. ;)
I quite liked it, but it is written with the X-Com fan in mind. Your average reader might struggle with things and concepts from the game thrown at them without a great deal of explanation. The main problem with the book being written for the fan is that the fan is going to pick up on the inconsistencies. The sheer scale of the forces on both sides in the final battle for example.
The one thing that did leave me unsatisfied was the subplot for the male lead. Or at least that's what I think he was. There was a bit of effort put into setting him up in a quite interesting and precarious situation, but then you cut back to the main plot and he just shows up again.