A server arrangement for controlling a video game viewable by game participants at a plurality of respective terminals. The server arrangement has a game engine to output graphical scenes collectively representing a virtual world with game characters, each graphical scene describing a portion of the virtual world. The server arrangement also has a shared-rendering engine for associating game participants with respective graphical scenes and for performing a shared-rendering operation on the graphical scenes to generate respective moving-image data streams, the shared-rendering operation being common for the game participants that are associated by the shared-rendering engine with the same graphical scene.