This is not a game about dividing a man into two parts using saws. It is a game about two ideologically conflicting views. The first view (and the view that seems to be winning) - is that the human race should not use cybernetic enhancements to expand their ability to do various things with materials, technology, and the human genome.
Set after Human Revolution, Mankind Divided is a lavish illustration of a police state and increasing tensions between the two dominant worldviews.
This follows the events of "the incident" where augmented individuals had a bogus chip implanted into their bodies, enabling them to become (against their will) murderous zombies - and this being unravelled as a terrorist plot.
As a result, augmented individuals are distrusted, disrespected, and feared. There's signs in train stations for "Naturals" and "Augs", green and red, just like traffic lights - there's so many little details that reference things like the social segregation of the US in decades gone by and the apartheid in South Africa.
For all the dystopian atmosphere in the game, Mankind Divided doesn't hide its influences well, or at all. There's so many references to Blade Runner and the Prague hub is very much like the office of the TV show Alias.
The story in Mankind Divided is very linear, with it for the most part being an on rails type adventure. You can explore every nook and cranny of the game world, but there's not much story there. There is, however, so much world building through details like in-game movie posters for fictional films, product advertisements, and other flourishes of attention to detail that make the game world just fun to inhabit, even through all the opression forced toward your character.
Several other things have changed between Human Revolution and Mankind Divided. Hacking is more difficult, owing to the introduction of a fog of war within the hacking minigame. This leads to several early game blunders where you spend way too much time reloading saves after you get destroyed by patrolling enemy forces while hacking.
The fog of war isn't the only thing that makes this game different. Unlike Human Revolution, Mankind Divided uses a customised game engine that doesn't scale very well at all. With a beefy system (R9 3900X, 32GB of RAM, 1080ti) the game chugs at times in 1080p (on a 144hz panel) - and even crashes in DX12 mode on a regular basis. Reverting to DX11 seems to fix this, and offers a huge increase in responsiveness.
The game has new augmentations, new weapons, and new mechanics surrounding all of this, while fundamentally being an expanded and continued Human Revolution. The only issue with this is that the story is ever so painful.
There's so much hopeless and pointless exposition where name after name after name of person, secret society, or governmental department, private military company or other faction that it reads like a thesaurus and dictionary for every conspiracy theory ever written. This is tiresome, as unlike the original title that started it all, very few of these have sub-quests you can explore in the game world, exerting your own little bits of influence and participation in these conspiracies.
Instead, you get "told" a story, the whole time.
The first and most basic point of story telling is "show, don't tell", and Mankind Divided tells you a bunch of things. This is in contrast to the lavish detail of its world, which through the colour grading, oppressive architecture, interior design, and carefully designed elements tells a story on its own.
Walking simulators would kill for this level of detail and world building through every scrap of paper that flows down their empty streets.
Yet somehow, as a complete package, it feels unpolished and unfinished, even though it has so much good going for it. There's so much more that it could do, and could be. It's a worthy title, but it could be so much more. With monetisation stacked on-top of a full-retail triple A single player game, it feels... like a money grab.
If you can pick this game up cheap, its a fun world to explore, but its tough to run, tough to endure (in terms of story) - but an absolute wonder to explore.
All screenshots taken from the Steam Store page for the game.