When Sim City was released in 1989, everyone was in awe of the concept of an open-ended game: a game that just cannot be beaten, that never ends. At that time, the dominant model was either arcade games which took about an hour to complete from end to end, or adventure games in a broader sense, that is games with a storyline that unfolds, where the players progress, save their games regularly and eventually kill the wizard and/or save the princess and get to see the end game credits.

Sim City 4, PC, 2003

Sim City’s latest episode. Even a city that complex can be developed and fine-tuned forever.

So that idea of an open-ended game seemed really novel. In fact, games were open-ended to begin with, the idea that there could be a conclusion took some time to materialize. In the early eighties, virtually all games consisted in a "level" repeated ad nauseam. As games became more complex, they got also more structured, with a well-defined beginning and end.

Today, while most games have an end, some categories are still, by essence, open: those organised around short and repetitive sessions like sport games or multi-player FPS, and inversely those with humongous content like MMOGs. Single player games which are open are still more the exception than the norm, but they do include games based on random (for instance some puzzle games) and games where the player nurtures their creation over time (Sim games). There are also "pinball type" games, that is games where the only possible conclusion is the defeat of the player, the only question being how long they can last (in practice, only casual games or bonus minigames are built like that now).

Today, the frontier between open and closed games is more blurry than it used to be:
 Open games tend to be more structured with scripted elements that can be triggered over several sessions. For instance, in the puzzle game Meteos, each played game gives the player points that can be later used to unlock new levels or special items. In sport games, the player can engage in a season with a beginning and an end. MMORPGs feature scripted quests and missions. Sim games have objectives that can be completed by the player.

Civilization, PC, 1991

While Civilization’s managerial gameplay is somewhat similar to Sim City, the game has an end. In fact, each game is short enough to ensure very high replayability.

 Closed games try to work on their replayability: they offer different game modes. Many games allow the player to replay some or all the content after the game is beaten, with additional features. Some games ask the player to define the settings of the game, with a very different experience depending on these settings. This is notably the case with 4X games such as Civilization or Master of Magic. Although these games do have a beginning and an end, they are very repeatable. Finally, PC games are often expanded by the fan community ("mods").