In the world of Watch Dogs the singleplayer and multiplayer exist in the same world and has been seamlessly integrated. Hacking other players will give you notoriety points which can be used to purchase upgrades such as nitro boost. To other players you will look like a random NPC in their game but in your own game your controlling Aiden Pierce in Watch Dogs multiplayer.
In the ctOS companion app mobile player control a helicopter and can challenge PC and console players to a race around the map. As the mobile player you can use the environment to your advantage and do anything to stop the other player from getting to checkpoints. This includes lifting bridges, explode steam pipes and control traffic lights for example.
Decryption Combat is similar to capture the flag where the objective is collect and decrypt a file. You and your team can use your phones to turn the environment to your advantage. All online activities contribute to notoriety points.
Watch this space as we approach May 27th 2014 when Watch Dogs will be out on PS4, Xbox One, PS3, Xbox 360, Wii U and PC.