The next-gen engine powering Ubisoft's Watch Dogs, Disrupt, will allow players to seamlessly connect and disconnect their game from others without causing major disruptions in the game environment or storyline progress, according to a post on the Ubisoft blog.
According to Watch Dogs senior producer Dominic Guay, Disrupt was built based on four major ideas: connectivity, dynamism, visible impact on the in-game city of Chicago and the flexibility to run on both current and next-gen hardware. Players will be able to seamlessly switch between playing online with others and disconnecting to play their isolated game without affecting the in-game environment.
"There's no loading or matchmaking or waiting for a game to start," Guay said. "That means that every single thing in the game needed to be ready to be synchronized with the network. Every aspect of animation and physics and the AI needed to work online with other players."
Other players will only be able to enter your game world by accepting a bounty contract bearing your name — after which they can stalk through your world until they're ready to take you down. This foreign player will look like a random NPC to you, so there won't be two versions of protagonist Aiden walking around. This multiplayer mode will be unavailable during story missions, so other players won't be able to interrupt your progress.
In Watch Dogs, all actions will have widespread effects. Rain will cause NPCs to pull out umbrellas and a strong wind will make them pull their coats tighter. Larger events, like car crashes, will cause traffic to backup and maybe push a few NPCs out of their cars to investigate. Aiden's actions will also affect how Chicago residents feel about him; stealthily taking down targets out of view will keep things calm, but running around openly killing people may cause NPCs to turn against him.
Read our interview with Nicholas Rioux, managing director of Ubisoft's Quebec City studio, on the challenges of making open worlds with next-gen hardware here.