Watch Dogs is an open-world cyberpunk adventure set in an alternative Chicago ruled by a pervasive computer system. The city is controlled by a privatised network named CTOS, which automates city travel and road infrastructures, as well as storing and analysing personal data on every single citizen.

But one man has had enough of this Big Brother nightmare. Aiden Pearce is a troubled computer hacker, haunted by a past in which his family has somehow been destroyed by the system. Now he wants revenge, and he knows how to get it. With his PDA and some tech genius, he’s able to hack into the city mainframe, gaining control over everything from traffic lights to train networks. And through a series of missions, he’ll use these abilities to bring some currently unnamed antagonist to violent justice.

A large team at the publisher’s Montreal office has been working on the game for four years, drawing its themes of hyper-connectivity, surveillance and data from research into current technology and urban theory. Indeed it’s a fascination with the concept of the ‘smart city’ that led the designers to start the project in the first place. “From the beginning there was the idea of connecting with everything,” says lead designer Danny Belanger. “That brought in a lot of cool mechanics and it challenged us.”

The tricky part, then, has been reining all the research in to make a coherent interactive experience. The result is a familiar open-world structure: there is a series of narrative missions and side-tasks, and a story that ends with one definitive conclusion. However, at any point, the player is able to scan passing pedestrians with the PDA, uncovering personal information about them; it could be that they’re about to be the victim of a crime or the perpetrator and the player can chose to intervene.

At a preview of the game in Paris we’re shown an instance. Aiden is wandering the downbeat Wards district, a poorer area just outside the main city. A button press will take Aiden’s gun out, but he automatically carries it in a concealed manner revealing the firearm will get pedestrians scattering, and wildly shooting will have them panicking and calling the cops. If you get to them in time, you can grab their mobile or hack it (an icon above NPCs shows if they’re on the phone to the police), otherwise your heat bar rises and a squad car will show up.

But Aiden has something more important to do than spooking passers-by and this is where the demo reveals an interesting structural component. Players don’t have the city’s entire data network open to them at the beginning each region has to be effectively unlocked by hacking a local CTOS terminal and gaining control. Once this is done, all the nearby data points become accessible.

For the demo, Aiden breaks into the secure CTOS compound, takes out the guards with an assault rifle, hooks into the network and opens up the sector. Now all systems are accessible via that handy PDA.

Reputation, it turns out, will be a key ingredient in the systemic element of the game. Every action in the game earns reputation points, so everything has to be considered. It is, of course, a familiar mechanic, but it’s interesting how Watch Dogs looks to weave the concept of consequences into emergent missions rather than into some kind of branching story.

There are other factions and secret groups. One, named Dedsec leaves tags and Banksy-like stencil graffiti all over the city. “There is a backdrop, an ecosystem to the game,” Morin tells me later. “You can’t align with other groups in a direct way, but there are shades of grey - you need to feel interconnection between different groups or else you’re not building a city, you’re just filling the streets with people. We’re touching on rebellion, the concept of using technology as a means to revolt, which is very close to current affairs - it was fundamental to us to build this in. There is Aiden’s story but there is a wider narrative that might broaden your perception.”

However, one of the most intriguing aspects of the game is its multiplayer component. Ubisoft isn’t saying much but we’re definitely getting some ‘massively single-player’ elements, like Dark Souls or Journey. Some side-tasks will give the player a target to watch, or an item to retrieve, but unannounced to them for this task alone their game will be merged with that of another player. From here, the two (or maybe more) participants will be either working cooperatively or competitively but it won’t be signposted, it’ll just be a seamless integration of game worlds.

In the game you have the ability to use surveillance, but you may also think, is someone watching me? I like the parallel with real life - there are so many cameras around us, watching us. Even in intimate moments, I have a camera on me, through my iPad, or smartphone”

The test is the play experience beneath all these tech toys. That’s what we won’t know about Watch Dogs until we actually play it and without doubt that is something we very much want to do.

Watch Dogs is released on PS3, PC, Xbox 360 and next-gen console platforms this autumn

Guardian News and Media 2013