We have been eagerly anticipating our first play of Watch Dogs since we first sat in a hot and sweaty demo room at E3 2012. It stole that particular show and raised expectations even higher when a bigger and better build was unveiled at this year's E3 trade event in June. There was only one thing we really wanted, however; we wanted to play the darn thing.

And play it we now have. Secreted behind closed doors at Gamescom 2013 in Cologne, Germany, Pocket-lint had a fairly lengthy play of a single-player mission on a PS4, experienced a slice of how the persistent online world can introduce other players into your game, and played the companion app versus console game that adds a whole new element to the title.

First, we had to infiltrate a base to find a security code and then hack into a system in order to allow us to get civilians' credit card details. The game is almost entirely based around the lead character Aiden Pearce's ability to manipulate and hack into electronics scattered around the vast open-world playground of Chicago, and we discovered exactly how intuitively that gameplay mechanic works, while having more than a spot of fun along the way.

Pearce can hack into CCTV cameras, people's mobile phones, and just about anything that has a computer or control panel. We managed to sneak into the complex by jumping from spy camera to spy camera, opening gates and turning on forklift trucks along the way to distract guards' attentions so we could creep past. One player we also saw on the Gamescom demo decided to just jump over the gate and blow the noggins off all inside. The end result was the same, they also accessed the mainframe, but the application (and morality) was totally different.

Once we could hack into mobile phones we stole a car à la Grand Theft Auto. This isn't the only direct comparison to GTA we could draw, but it definitely has the same feel as the enormously successful franchise. Basically, there's a great driving engine inside the game and whizzing about in different cars is a thrill. Even more so when you can manipulate the traffic lights along the way to both clear your path and cause havoc behind you.

Making our way to a more affluent area - the sort of place where a potential victim would have enough cash in their bank account to make it worth pilfering - the demo took a sudden twist: somebody was trying to hack us.

This was an example of how friends or other gamers can enter your world and interact with you directly. Once the hack is started, you are alerted and must therefore find them to stop the attempt before they steal your in-game IP address, ready to poach bonus items and the like in future. The one problem is that, while they look like Aiden Pearce in their game, they take on the persona of an NPC in yours.

The way to wheedle them out is up to you, but you will be able to see tell-tale signs, such as somebody running in a place where the other NPCs all walk. Pocket-lint was told that one way somebody did it in the demo was to fire a gun in the air. The NPCs all ran leaving one person - the rival - standing still for a split second.

We also felt what it was like to retaliate. This time we appeared in the protaganist's own game world, looking like an NPC, and we tried to hack his phone. After you start the hack, he is looking for you and you need to blend in with the surroundings while the download completes. Unfortunately, we shot him when he discovered us, which ruined the hack, but we certainly got the point.

Then it was onto a different demo PS4, which was set up to purely interact with the smartphone and tablet companion application that will be released at the same time as the game.

The person using the app - which can be over 3G, so doesn't have to be in the same room or even indoors - is a kind of overlord. They have a top down, wire frame view of the playing area, which is dotted with static and moving icons. The app player controls a helicopter primarily, but can also set traps and manoeuvre the police into strategic points.

This is all because the point of the game is for the app gamer to stop a player reaching a set number of checkpoints in an allotted time. The player, using a console, can jump into cars, peg it on foot or try to get to the points anyway they can, but must also be wary of the traps and explosions along the way. It's a simple idea executed brilliantly.

The app is designed perfect to be controlled on a touchscreen, while the mini-game is a real thrill to play on the ground. We tried both before our Gamescom Watch Dogs session was over and left very satisfied indeed. We cannot wait to play the final version, it really does seem to be living up to the last year or so of hype.

Watch Dogs will be available on 22 November on Xbox 360, PS3 and PC, 29 November on PS4. It will also be a launch title for Xbox One, coming out at the same time Microsoft unleashes its new console.