After watching the whole thing, here's a bit more about it.
The Good:
-A very action-packed first episode that throws you right into the action and never lets up.
-There's lots of potential which, I imagine, will be retroactively developed and presented in order to explain how things ended up like this. The series definitely has strong Giant Robo vibes. The entire cast gets in on the action, with or without robots, and it probably won't just be Kouji blowing the enemies away on his own. Some bits of characterization might also be interesting, from what little I managed to understand.
The Bad:
-For a first episode, this is definitely very confusing, even for those familiar with the material, and might be getting ahead of itself. Lots of characters, new and old, are introduced and used in a very short time without too much exposition. I am assuming that the series will go back to a more reasonable pace next week, but this could turn some people off if they aren't patient enough.
-Sometimes the animation does have its weaker points, even if it generally looks great. Although that doesn't really bother me, hopefully this doesn't mean there will be budget problems further down the road. Imagawa is allegedly infamous for spending too much during Giant Robo, which was an OVA and not a TV series. It would be a shame if that became a big issue here.