Started this up again yesterday and have just completed chapter 9. Not going to spoil anything but it took me a number of attempts to complete the final fight as I had the Owl setup wrong on first encounter. For reference don't set it up as a shield as it is useless for this part. The delay in recall and trying to stun, coupled with a lack of adrenaline caused many an outburst!
EDIT: Sorry I mean half way through Chapter 9. I have just checked and I havn't completed the second bit yet which looks even more frustrating.
Interestingly the massive fight at the end of chapter 7 only took me two attempts. The first time I died because I didn't notice the shielded enemies coming up the platform. I found the best weapon for this segment is the large RPG like energy gun. It can take out the shielded enemies in two hits and every other enemy in a single shot. Ammo is plentiful on the rack directly behind you. I also found it VERY benefitial to start the battle by laying down every trip mine available - preventing the enemies from getting onto the platform you are defending. (I can't remember if I am playing on Hard or Normal so the amount of shots may vary).
The turret section was a pain but as long as you remember the enemies coming up onto the platform it isn't TOO bad.
Overall I am enjoying the game (after a break) but I can't see myself replaying it again.