Information processing system and information processing program

1. An information processing system that provides a participation type of an in-progress multiplayer game, said information processing system comprising:

a storage for storing game information that is necessary for progress of the in-progress multiplayer game;

a server that is configured to, for an occurrence of an addition of a new player to the in-progress multiplayer game before the game information is reproduced:

acquire a request to allow the in-progress multiplayer game to proceed from each of a plurality of players participating in the in-progress multiplayer game;

change the game information according to the request, and storing the changed game information in the storage;

store in storage log information indicating a relation between before and after the game information is changed; and

use the log information to reproduce game information older than a first point in time of when the new player enters the in-progress multiplayer game until the game information reaches the first point in time, wherein the server uses the log information to reproduce the game information from older than the first point in time to the first point in time when the new player has joined the in-progress multiplayer game, and the game information reproduced by the server to reproduce the progress of the in-progress multiplayer game is configured to be provided by a client of the new player, such that the client of the new player reproduces the in-progress multiplayer game from the game information from a time older than the first point in time to the first point in time when the new player is added to the in-progress multiplayer game.

2. The information processing system according to claim 1 , wherein the server is configured to store as log information at least part of the game information changed by the server, compare newest game information stored in the storage with the game information stored as the log information, and determine whether or not the newest game information and the log information have been synchronized.

3. A non-transitory computer-readable medium including stored instructions executable by a processor, that provides a participation type of an in-progress multiplayer game, said stored instructions causing the processor, which is capable of accessing a storage that stores game information for progress of the in-progress multiplayer game, to perform the instructions that comprise, for an occurrence of an addition of a new player to the in-progress multiplayer game before the game information is reproduced:

acquiring a request to allow the in-progress multiplayer game to proceed from each of a plurality of players participating in the in-progress multiplayer game;

changing the game information according to the request, and storing the changed game information in the storage;

storing, in the storage, log information indicating a relation between before and after the game information is changed by the changing;

using the log information to reproduce the game information from older than a first point in time of when the new player enters the in-progress multiplayer game until the game information reaches the first point in time; and

using the log information to reproduce game information older than the first point in time of when the new player enters the in-progress multiplayer game until the game information reaches the first point in time,

using the log information to reproduce the game information from older than the first point in time to the first point in time when the new player has joined the in-progress multiplayer game, and wherein the game information used to reproduce the progress of the in-progress multiplayer game is configured to be provided by a client of the new player, such that the client of the new player reproduces the in-progress multiplayer game from the game information from a time older than the first point in time to the first point in time when the new player is added to the in-progress multiplayer game.

4. An information processing system that provides a participation type of an in-progress multiplayer game, said information processing system comprising:

a storage configured to store game information that is necessary for progress of the in-progress multiplayer game; and

a processor comprising instructions to execute:

acquiring a request to allow the in-progress multiplayer game to proceed from each of a plurality of players participating in the in-progress multiplayer game;

changing game information according to the request, and storing the changed game information in the storage means;

storing log information in the storage, the log information indicating a relation between before and after the game information is changed by the in-progress multiplayer game;

for an occurrence of an addition of a new player to the in-progress multiplayer game before the game information is reproduced, using the log information to reproduce game information older than a first point in time of when the new player joins the in-progress multiplayer game until the game information reaches the first point in time; and

utilizing the log information to reproduce the game information from older than the first point in time to the first point in time when the new player has joined the in-progress multiplayer game, and wherein the game information used to reproduce the progress of the in-progress multiplayer game is configured to be provided by a client of the new player, such that the client of the new player reproduces the in-progress multiplayer game from the game information from a time older than the first point in time to the first point in time when the new player is added to the in-progress multiplayer game.

5. The information processing system according to claim 4 , the processor further comprising instructions to execute storing as the log information at least part of the game information changed, comparing newest game information stored in the storage with the game information stored as the log information, and determining whether or not the newest game information and the log information have been synchronized.