Replay value or replayability is a term used to assess a videogame's potential for continued play value after its first completion. Factors that influence replay value are the game's extra characters, secrets or alternate endings. The replay value of a game may also be based entirely on the individual's tastes. A player might enjoy repeating a game because of the music, graphics, game play or because of product loyalty. Dynamic environments, challenging AI, a wide variety of ways to accomplish tasks, and a rich array of assets could result in a high replay value.
A game with a linear plot will typically have a lower replay value due to the limited choices a character can make. Games that offer more choices in regard to what the player can do, such as strategy games, roguelikes or construction and management sims, tend to have higher replay value since the player might be able to make each play through different. In the case of role-playing video games, plots can be linear or non-linear. The plots of older RPGs tended to show little to no plot changes with each play through. A good example of an RPG with a non-linear plot is Mass Effect and its sequel, Mass Effect 2. Role playing games released in later years allow for more freedom. For instance, choosing to be ruthless instead of lenient might prevent certain events from taking place (or even cause new ones to occur). Likewise, allowing a particular character into the party could cause the plot to branch off in a new direction, if even for a short time. A good example of this point is the character Juhani in Star Wars: Knights of the Old Republic. The player has the option of killing her or sparing her life. Should the player be merciful, Juhani joins the player's party. Later in the game, the player will then run into an enemy from her past.
This is the ability to play as different characters each time through the game. For example, the game Diablo allows the player to choose one of three character classes: warrior, rogue, or sorcerer. Party-based RPGs can have a good degree of replayability, even if the plot is essentially linear. The plot of the first Final Fantasy game remained the same with each play through, but since the player was able to choose their party of four from six different classes they could choose a new party configuration with each new game. The Final Fantasy instruction manual even gave the player ideas for different types of parties (well-balanced, heavy magic use, combat oriented characters, etc.). In the first Final Fantasy game you can choose from the classes of Fighter, Thief, White Mage, Black Mage, Dragoon, and Red Mage, providing the player with 15 possible character combinations with 4 distinct classes, or 126 with repetition.