I loved the first one (not as much as most people though) and was very disappointed in this one. I understand the graphics are great, the enemies react in various ways and the story is way cool. Well it sin't but it could have been. There are many nice touches like having to sneak on and photograph the big mech at one point and such.
but...
i found the game to be pretty boring and repetitive. The story kinda progresses, there is a plot, but i didn't care that much about it. The first mission is actually very good, but the rest of the game is on a big platform thing which is ugly, and everything looks the same. You're going back and forth between the few rooms there are all the time. At least the game isn't too difficult or too long.
Very cool ideas, nice touches, but the core of the game is very weak, so i didn't get into it very much.