This application is directed to presenting a unified user interface on a network-connected television device. The unified user interface displays media content recommendations selected and organized based on knowledge of a user (e.g., search queries, search results, watch history, purchase history, physical activities). The unified user interface also includes a focus area for displaying a series of media content items (e.g., an advertisement) sequentially according to a temporal order for the purposes of promoting a media content item, product, event or service. In some implementations, playback of a media content item presented on the unified user interface relies on a collaborative implementation of a corresponding media player application and a media content casting application, particularly when the play involves a restricted mode. The content casting application is enabled to play the media content item at the restrict mode when the media player application does not operate in the restricted mode.