City Hub
Detroit is probably the size of Hong Kong in the original game and requires no loading for outside environments. It includes a Limb Clinic, several Apartment Complexes, the Police Station demoed at Gamescom, a criminal neighborhood and a lot of roads. People are living their lives there, some smoking sigarettes, some playing on their phones, even a punkster dancing in the subway station.
Experience
You earn experience by completing objectives in missions, both main and sidequests, by completing objectives without being seen, by killing armed NPCs and by exploring. You will get more for non-lethal as well as from takedowns. How this will turn out in balance is to be seen as I cant tell for every player. However, it is safe to say that anyone who kills no one but does a non-lethal approach gets more points IF he attacks all enemies. A hostile player in its turn is more likely to shoot everybody, but will get less points per head.
AI
AI is great, though there are still some bugs when they dont respond to seeing you quick enough. I assume this will be fixed over time. The AI combines the best of Splinter Cell and Rainbow Six while maintaining a DX feel. They have 4 stances: neutral, suspicious, alarmed and hostile. In normal they do their routine, in suspicious they suspect you are somewhere, in alarmed they know you are somewhere but not where and in hostile they will attack. Hostile enemies will search for cover based on their preferred range. Fir example, I saw a sniper running to the back of a level to keep his distance from me.
Freedom of Exploration
Overall I'd say that, though the main missions are still shaped in an go from A to B way (except for the city missions), there is plenty of room for exploration. First, I want to point out that DXHR is competing with nostalgia. That is, the original game also had a lot of go from A to B mission with some side paths, but in memory only the best parts remain the longest. Id compare most missions Ive seen until now with missions like Airfield or MJ12 Prison, again except for the City missions. In Detroit, the only city seen so far, almost every part of the level is connected, either by sewers or by vents. For the police station I found 4 entrances for example. Highlighting does help in discovering, but Its mostly your own ability to thing about the obstacles logically. For example, if a path is blocked by electricity, some players will instantly know they can use crates to cross it, while others will not. This is not relying on highlighting. As such, its hard to determine whether the game is more or less complicated than the first game, since I already learned a lot of tricks from the first Deus Ex.
World Depth
The amount of work put into the world is stunning. JJB jokingly said they could fill an Ikea catalogue with all their furniture etc, but he's actually right. Ive rarely seen a gameworld filled with so much content. They made tons of brands, just being advertised on the streets, they made fasion, they invented technology. For a cyberpunk universe, DXHR is simply great and for gaming as a whole, it has little competition. Furthermore, the game is filled with easter eggs and coversations and emails giving extra depth to the game. I wont spoil them, but I had a lot of laughs from hidden stuff throughout the game.
DXHR vs DX
Like I noted before, its hard to compare DXHR to the original due to nostalgia. But I can say this: the combat and stealth are better. Period. AI responds better and aiming/shooting is spot on. COver based stealth just works better than light and dark without knowing whether you are actually hidden, and its easier to trick the AI, making them seem more human. I still did miss some extra deep conversations though, which is mostly caused by the fact that the ost people you meet in the beginning of the game are already hostile. While Gunther, Anna and Walton where introduced as friendlies, Barret and co are instantly enemies and it will probably take untill later in the game before they will be given more depth. Pritchard and Sarif are interesting though and I'm eager to see more people.