Average game for first couple hours. After that it's great and difficult to put down. Freeze in time and shoot.
The atmosphere was cool, reminiscent of initial Bioshock experience, but it wasn't quite as good and totally lacked the powers. However perhaps it's 1/3 of the way through shortly after you get your TMD (takes just a bit after TMD as I was dissapointed for a few minutes longer) and finally get to start customizing weapons and get abilities and customize them the game is great I played it all night. I loved shooting a dome of energy over enemies basically freezing them in time and then running up to them and blowing them to bits and watching that happen once the time stopping dome expired a few seconds later. It's great to shoot an exploding canister in the time stopped dome and wait and watch time resume and have it explode around the enemy.
The story was entertaining enough and some of the AI allies were fun to work with and get their story. I felt I got to know/understand the AI com-padres more than most games.
If you enjoy an fps with a good atmosphere and powerups you'll love this game, it just takes a couple hours to get to the fun powerups. Additionally the TMD device has several functions which the game exploits with some puzzles not all that dissimilar to Portal.
FYI, it may be relevant, I played this game with a xbox 360 controller oh and it was annoying it not referring to controller buttons it just said like pad 1, pad 6 - I glanced at controls for xbox on gamefly and that helped a ton. Without the 360 controller it can seem a bit overwhelming so many keys to mash frequently as there are several good abilities you don't just use 1 all the time (at least not until towards end game and you have maxed out an ability).