Game jams, including Ludum Dare, the Indie Game Jam, the Nordic Game Jam, and the Global Game Jam, are typically annual competitions in which game developers are given a theme, concept and/or specific requirements and given a limited amount of time, on the order of a few days, to come up with a game prototype to submit for review and voting by judges, with the potential to win small cash prizes. Companies can also have internal game jams as a means to relief stress which may generate ideas for future games, as notably the case for Double Fine and its Amnesia Fortnights. The structure of such jams can influence whether the end games are more experimental or serious, and whether they are to be more playful or more expressive. While many game jam prototype go no further, some developers have subsequently expanded the prototype into a full release after the game jam into successful indie games, such as "Superhot", "Super Time Force", "Gods Will Be Watching", "Surgeon Simulator", and "Goat Simulator".