I am new to the site and new to critiquing so I am hopeful that you can find my comments useful.
- Your explanations/ descriptions come too quickly and appear to me a little forced, for example
Michael Willis, a representative from Mordecai Universal Technologies,
Colonel Reno, of the 1st Marine Infantry Parachute Regiment - 2e Compagnie,
Sarah Pearson – an expensively suited observer from the Institute
I am working on the basis that we will have a an entire book to get to know these characters so there is no need to rush out the name tags early. If one was looking into a room as an observer, one might see the 'Military Officer in charge, they guy in the dodgy tie and the woman in the flash suit, and work out who they were and what they did over the course of the first few minutes', and perhaps the reader could do likewise. I appreciate however that is purely a stylistic comment.
Also
The gigantic edifice, commonly referred to as Un Ècran, had become far more than just a shield to act as a last line of defence - it had grown to be a symbol of defiance and hope to a beleaguered world.
(Haven't worked out the quote function yet, Sorry)
Wouldn't Un Ecran, be the first line of defence? You reference Hadrien's wall and indicate the threat is coming out of the rift, so the barrier is the first thing they hit, not the last. Minor I know