Just beaten this, thoughts below:
WOW, I wasn't expecting this given the mediocre reviews. I thought it was going to be another mundane TPS like Dark Sector, Infernal or Prototype, but what I got was a cross between Mass Effect and Gears of War (and a more enjoyable TPS than the latter).
+Epic boss fights and lots of them
+I love squad based shooters and especially those that force you to mix your party up so you don't just use the same characters through the whole game
+Interesting storyline that actually got me thinking about the morality of the the whole thing (e.g. does a hybrid who has lived their whole life believing themselves to be fully human, and is biologically human really deserve to be executed?)
+Good graphics IMO aside from a few sections, the characters look great and have excellent animation (facial expressions etc) for the most part, far superior to many AAA titles. The screenshots on the Steam store really don't do it justice.
+Voice acting is pretty good, except for Rachael
+I'm a bit of a sucker for RPG elements like upgrades in shooter games, and it works well, especially as you get rewarded with credits for headshots, multi-kills etc i.e. a bit like Bulletstorm, there is actually an incentive to have spectacular combat instead of just hiding behind a crate blind-firing.
+Good cutscenes for the most part
+A few spectacular set pieces albeit not quite Max Payne 3 standards
+Interesting respect system i.e. how you interact with your teammates affects how they interract with you
+Nice damage system i.e. you can literally shoot robots apart piece-by-piece, perhaps going for the legs first to slow them down, or a headshot to send them haywire, or just chipping off the armour to find a weakspot.
-Can't set the controls (including FOV and sensitivity!) from inside the game, you have to quit, guess the most appropriate setting in the config tool, start the game again, continue your game, find the sensitivity is still wrong, quit, load the config tool..... yadayadayada
-Mouse doesn't feel quite right, when it the menus it just detects movement rather than having a cursor, and in game it feels like there is accel or it is emulating a controller or something.
-Didn't really get the love story, Faye seems really standoffish telling me to take my paws off when patching up her wound and then literally the next minute I'm banging her
-Maybe a bit too easy
-The conversations start to wear a bit thin towards the end, especially when you have to bat back 3 comments or whatever before the door to the next corridor will open
-Massive plothole surrounding the whole Hollow Children living undetected for years things.... have they never heard of x-rays? Heck, near the end of the game they even use their own portable scanning device to prove that a particular character is a robot.....
-60fps cap and seemingly no way to remove it
Overall this was a very pleasant surprise and I'm glad I gave it a bash, one of the best games I've played in a long while.