A client system presents, within an execution environment of an application, a third-party media stream distinct from the application, received from a remote host server via a network. The client system detects interaction events during presentation of the third-party media stream, and transmits descriptions of the detected interaction events to the remote host server. The application may be pre-cued prior to presentation, e.g., to minimize start-up time. In some implementations, a side-band message channel is established to facilitate communication between the client system and the remote host server.