Sunset Overdrive was still in development when the Xbox One gained a 10% power boost via freeing up previously unsable CPU processoring that was reversed for Kinect. At the time the game was slated to render at a 1600x900p resolution, but many were hopeful that with the power boost it could render at 1920x1080p full HD. When the game finally released though it still retained it's originally planned 900p resolution. Insomniac, the development studio, explained that they indeed were able to get the game running above 900p with the power boost, but instead opted to use the extra power to render more enemies on screen since they were already satisfied with how the game looked at 900p.
On the portaloos that you come out of when you fast travel , there is a logo of three shells, this is clearly a reference to the "three sea shells" a recurring joke in the film demolition man