Ok, impressions.
I like all the life that is infused into the city through the people, the civilians. You can find any kind of behavior in them. Walking around, jogging, doing yoga in the park, dancing, rapping, playing music, talking in groups, discussing, fighting, stealing someone at a ATM, drinking a coffee, and well, etc etc. It increased the immersion nicely.
After that, we have the possibilities of hacking into npc's info. It looked like silliness in the video previews imo, as they presented it as something revolutionary and with infinite possibilities of spying into anyone's life in the game, while the truth is just a random database entry picked and shown in the game. But hey, even if it isn't really tied into the gameplay (actually, you can win some stuff doing it, as explained some posts above), I have to say that it adds to the immersion of the game, it gives it a bit of soul, so it isn't worthless. It's strangely addicting to be voyeur-like and read their private sms or hear calls that clearly weren't meant for your ears. There is of course a good number of them, from the amusing to the colorful to the jokingly to the asshole-ish. There was one about a plumber and pipes full of semen that...
Talking about being a voyeur, there is a specific activity to hack into someone's router and see them in their home, doing stuff like cooking or doing exercise with something like kinect fitness (conspiracy lovers were right, the kinect camera is a trojan for NSA!). In fact all I think all this personal invasion you can do is done searching to touch the social real life issue of security vs freedom, the privacy in this future world that is increasingly more connected, etc.
It could be said that the main character is contradictory, as he seems to have big issues when someone stalks his family or through the story the company behind the CTOS are presented like evil corporate data-stealers and data sellers (*cough* Facebook or Google) but he doesn't have a problem when he does the stalking and the invasion of privacy. I think this hypocrisy of the character is a feature and not a bug, showing that even if you believe yourself to be the "good guy" and doing illegal stuff for a "good cause", the slippery slope is dangerous and in the end you aren't much better than the big evil companies.
BTW, as expected of a game about a hacker, there is a hacking minigame, used in specific points in the story or when you hack into a new CTOS central. It's pretty decent thanks god, though in the easy side.
We also have the typical "climb the tower" activity from AC series and Far Cry 3, but I think here it's a bit better as it's basically a small puzzle to solve exploring the buildings around, following data lines and hacking, instead of just pressing one button to climb up, doing some small left or right turns from time to time.
The main plot is right now in a point I would call "neutral". It isn't bad, it isn't good. It seems slow, as right now in the second act the real conflict hasn't shown. The main character is bland.
The game has a curious reputation system where if you kill or hurts lots of civilians and cops your rep will drop, and if you stop crimes it will rise up. Some people can recognize you on the street, and depending of said reputation they will call the cops or instead will want to make a photo of you and be proud of it. Though unless you go crazy killing civs it isn't an important factor, the normal progression of the game should make your reputation to go positive as you stop crimes from time to time.
When you do a crime if a civ sees you they can call the police, you can stop the call aiming at them with a gun, it's a nice touch.
In the gameplay, lots of times it reminds me a bit to Splinter Cell, as it's a mix of third person cover shooter and stealth (though not as complete and polished as SC Blacklist in that regard). You can creep around from cover to cover unseen, using gadgets to distract guards, meleeing them silently, using a silenced pistol, hacking the world to help you and distract them, or you go can go loud, or a mix of both. Pretty different than the usual GTA mission, in other words. The set piece design also reinforces this, usually there are 2 or 3 entrances to the hostile area, there is some verticality built into it, etc. It isn't Deus Ex but it isn't linear.
I like the CTOS base intrusions in particular, where you can use combat or stealth to reach the router, or even another way to stealth them, hacking cameras and the environment doing a kind of spatial puzzle to reach the objective without even moving around. There some nifty stuff you can do like blowing up a transformer to make a guard move around that point and use that to hack in his AR goggles and see through his vision in that area to reach the goal.
Weapon combat is fast and lethal. You die fast, the enemies also die fast. Using stealth and hacking is more rewarding, normal firefights are easier imo, even if you die fast, using the cover system and the health regen and your ample arsenal should make easy work of them (playing on hard).
In the vehicles, handling feels... a bit off. It's still fun to do some checkpoint race missions, but it isn't a racing game. Though not as bad as GTA4. When you are being persecuted by the police, they are aggressive and will get close to you easily, I think the goal here is to make the player use the hacking opportunities to win over them, instead of just losing them by pressing the forward key.
When they lose you, they will start seeking you patrolling, establishing checkpoints, using a chopper (well, it depends of the search level of course), in that moment you can try to get away and put distance or go from alley to alley avoiding them and turning off the engine. A bit of stealth with cars, if you want. Once they give up, they still will try to locate you by scanner, which basically means some yellow circles that grow and move in the minimap and you have to avoid.
The game has a very decent amount of content, as expected. Ignoring the main missions, you have
-"stopping crime" activity
-18 convoy missions (kill a vip in a convoy)
-15 hideout missions (these are pretty cool, basically they are the Far Cry 3 missions when you have to go to an enemy base base and kill the leader with melee, here you have to use the baton and the gameplay is strongly Splinter Cell-ish).
-40 agent missions, with 4 types. 10 each, I supposed. These are more focused on vehicles, like interception missions, transport missions, evasion missions.
-several types of mini-missions. From discovering smuggling weapon spots to missing persons to discover QR codes in rare places, and a few more. They are a mix of collectible stuff with some light gameplay (you have to hack a bit, or you have to search a specific camera that gives you a specific view).
-13 CTOS towers.
-7 or 8 CTOS bases.
-16 CTOS intrusions.
-30 privacy invasions activities.
-Moar collectibles: songs, audio records, hotspots, etc
-Games: poker, shell game, drinking game, several chess puzzles, slot machines.
-Videogames: 2 AR games, one pretty boring of killing waves of aliens, and a better one running around in a circuit taking gold coins. And 4 VR games / digital dreams. Some of them aren't 5 minute diversions, but they have their own XP tree with perks, even.
-Online activities and hacking, of course.