Spark IV is an application primarily used to open, view, and edit some of Grand Theft Auto IV's properties. These include the script libraries, texture, and models in the game. All of the data for manipulation is listed in this application's main pane. Through the tree-list view, clicking on a property on the left side of the interface enables the player to view that particular file's content on the right side of the interface. Users who wish to modify the game with external GTA IV files can use the import button. There is also the export button, which places edited files in the game for use. Modifying some of these file properties can trigger changes in Grand Theft Auto. These mods vary. For example, some modifications give all characters in the game firearms and other deadly weapons.
Grand Theft Auto IV is a proprietary sandbox game wherein the player takes the role of Niko Belic, who comes to the States only to become part of the world of organized crime. Most of the game's missions can be done in a non-linear fashion. The missions are necessary to finish the game's story.