So impressions, first of all I'll say that if you liked Human Revolution then you'll like this one as well, I'll break down some aspects of the game that I can think of and post my views on them. My post will be a bit disjointed because I'm writing it as I think it through so sorry about that. Also it took me about 23 hours to finish a pacifist run on Give me Deus Ex difficulty level, I tried to ghost as many areas as possible.
Gameplay: Think of this game as an evolution of Human Revolution, Deus Ex games have always allowed you choices in terms of encounter but they have also always been rather clunky in their implementation resulting in one playstyle having an advantage because you don't have to fight the system as much. Shooting has been the one that has always been off in these games but they have streamlined some elements to make offensive style feel better if that is what you want. For instance the scope sway is not as severe anymore, reloading is faster (there is an aug to make it even faster) and some guns like stun gun don't need to be reloaded after each shot. The new augs like are split between playing defensively and offensively. Augs like Nano blade, tesla shot can be activated quickly in the head of the battle to take an enemy out. You can use the Icarus dash for omnidirection dash, covering gaps, leaping to higher ground...and you can also use it to dash into an enemy like the biotic charge in Mass Effect. The control scheme specific to Mankind Divided allows for this style to be played better because in addition to mapping 4 augs to the D-pad you can also map an additional one to L1 (It's the only scheme that allows this). In addition to your usual goons you also fight augumented enemies, flying sentries, enemies in power armour etc providing for a more varied enemy design than HR.
Non linearity: This is the heart of Deus Ex. The game has multiple paths littered around everywhere, yes there are lots of vents, although this time around lots of them are higher and hidden behind things than being on floor level easily visible. But it's not just vents but doors, ledges etc. Coming back to a previous area in NG+ with additional augs made me discover routes that I missed the first time around. Sometimes you can use the objects in the environment to circumvent the lack of having an aug for instance in a mission where I had to get something from someone by talking (which could lead to another side quest). I could completely bypass this by simply getting to a ledge that led me above the room and I made my way across to the main room and got that thing without ever having a conversation. I didn't have high jump so I just stacked 2 boxes on top of each other to get there the game didn't mind. While I was making my way around I noticed that there was another path that I could have taken that would have led me to this area. I could also complete some objectives before I am even told about them and the game would acknowledge this. Then there are times when the game tells me I have to make a choice between two objectives which I can choose to make or I can simply ignore the game and try to achieve both provided I am quick and clever about it. You receive most of the side quests by talking to people, so if you don't do that then you don't get those side quests. As mentioned in my example previously in this paragraph, sometimes you can do things in a certain way that could lead you to not having any conversations at all and hence no side quests. There was actually a point where I infiltrated into an enemy lab, disabled some machine producing toxic gas and made it out and I still don't know if it was suppose to be part of some quest or not...lol. Very similar to HR but again, it's implemented better here.
Presentation: The game is a looker. It might not have amazing animations, and might not have the most technically impressive visuals but it is still quite high up there and mixed with the fantastic art design it looks great. Golem city is impressive so are parts of Prague in later half of the game. The ambient and background music are absolutely amazing. You can toggle on and off every HUD feature and some of them can be set to fade in and out. Although, I would have preferred for the sharpness filter to be toggleable though. Also it should be worth noting that the performance on PS4 is not flawless, the game has a soft V-sync solution and it does tears and drops frames when you are walking around in large areas in the hub when there are multiple NPCs and lots of geometry on screen, it's not too big of a deal because it does not persist for long. But it should also be noted that during the missions themselves the performance is stable and I did not see any tearing.
Environment: Despite being set only 2 years after HR, the game feels more futuristic and cyberpunky. You can see that technology is everywhere in this world. Prague is a massive hub and the areas do not feel artificially blocked by cars and other objects as you saw in HR. The environments in this game are densely packed with computers to hack, rooms to break in for loot, datapads to find and alternate routes to take. Tons of buildings can be entered, plenty of them don't even have any purpose mission wise and they just exist to give the city a natural look. It's hard to talk about variety in locations without spoilers but some people might be disappointed depending on what it is that they are looking for while some people might find it thrilling. For instance, eventhough Prague is one hub there is a lot of variety in the of environment you can find, with corporate buildings, gang strongholds, police stations, underground hideouts etc and at times even out in the streets...they look varied and provide a different gameplay experience. Without spoiling much I'll just say that the daytime Prague videos you've seen is not all there is to the city. And there are other areas you go to outside of Prague, Dubai and Golem city.
Story: So this is the bit that has everyone agitated. Some reviews have claimed that they felt as if they were 50-60% through the game and then the game ends abruptly. I simply cannot see this happening if you were paying attention even slightly, because things escalated in a natural order and I was able to tell that I am nearing the end easily. Before we talk of payoff we have to understand what the plot itself wants to do. For instance, if the main plot is about going after a dude to catch him, then you can't be disappointed about not being able to destroy the Illuminati at the end of the game. It's not fair to complain about things that way, beside something like the Illuminati would have plot armor because they exist in Deus Ex 1. You have to make connections like that and make sense of things. In any case the story is basically right in the tittle of the game, mankind divided between augs and naturals and there's stuff going on that will change things, it's quite above average for a video game story and you owe it to yourself to find details in the environment to understand more. Some people have expressed that there is no resolution at the end and lots of questions are left unanswered. I will disagree with them because while there are threads left open to follow up, the game itself does not end in a cliffhanger and addresses the plot and subplots with a conclusion. Whether it is enough or not is up to an individual, for me it was enough as it allowed the game to focus on the story it sets out to tell without feeling disjointed. The side quests have their own interesting little stories and one of them in particular was quite mid 20th century noire. Also...there is a mid credit scene that you need to watch.
Let me know if you guys want me to add anything else.