1. A method for operating a computer game to include updated content after the computer game is installed on a client, the method comprising: operating an interactive computer game on a client to provide a game output including a display of a modeled environment in which game events occur and modeled objects appear, wherein the modeled objects comprise updated objects that are stored at the client, and the updated objects are defined by object properties for determining timing and appearance of the updated objects in the game output; maintaining the updated objects at the client by communicating between the client and a remote server after installation of the computer game on the client, to update the updated objects stored at the client at different times after the installation is completed; and controlling use of the updated objects during operation of the computer game based on their respective object properties, using an integrated engine controller component of the computer game, to cause selected updated objects to be included in game output according to predetermined control parameters.