FUNDAMENTALS OF GAME DESIGN, SECOND EDITION
Ways of Saving a Game
Over the years, designers have devised a variety of different ways to save a game, each with its own pros and cons for immersion and gameplay.
If your game runs on a device with no storage at all (a rarity nowadays), you can't save the game in the middle of a level, but you can let the player restart the last level attempted. Each time the player completes a level, give her a unique password that unlocks the next level. At start-up, ask if she wants to enter a password, and if she does so correctly, load the level unlocked by that password. She can go directly to that level without having to replay all the earlier ones. This method also allows her to go back and replay any completed level if she wants to.
The player may interrupt play and save the current state of the game either to a file on the hard drive or, more usually, to one of a series of named save slots managed by the game program. When the player wants to begin the saved game, he tells the program to load it from the directory of files or slots. This allows the player to keep several different copies, saved at different points, and to name them so that he can remember which one is which.
Unfortunately, although this is the most common way of saving, it's also the method most harmful to the game's immersiveness. The user interface for managing the files or save slots necessarily looks like an operating system's file - management tool, not like a part of the fantasy world that the game depicts. You can harmonize this procedure better with appropriate graphics, but saving almost always takes the player out of the game world. Some games salvage the immersion to some degree by calling the file system the player's journal and making it look as if the saved games are kept in a book.
Fast-moving games in which the player's avatar stays in more or less constant danger (such as first-person shooters) frequently offer a quick-save feature. The player presses a single button to save the game instantly at any time, without ever leaving the game world. The screen displays the words Quick saved for a moment, but otherwise the player's immersion in the world remains undisturbed. The player can reload the game just as swiftly by pressing a quick-load button. The game returns immediately to its state at the last quick-save, without going out of the game world to a file-management screen.
Disadvantages of quick-save arise because saving so quickly usually means the player doesn't want to take the time, and isn't offered the chance, to designate a file or slot. Such games normally offer only one slot, although some let players designate a numbered slot by entering a digit after they press the quick-save button. Players remember which slot is which when quick-loading. Quick-save sacrifices flexibility to retain immersion and speed.
AUTOMATIC SAVE AND CHECKPOINTS
A few games automatically save the state of the game when the player exits, so players can leave and return at any time without explicitly saving. This harms the player's immersion least of all, but if the player has recently experienced a disaster, he has no way to recover from it. More often, games save whenever the player passes a checkpoint, which may or may not be visible to him. Checkpoint saving is less disruptive than quick-saving because the player never has to do anything. The player can go back and undo a disaster, provided that the disaster happened after the most recent checkpoint. But it means that the player can't choose to save whenever he wants or choose to restart at some earlier point. If the checkpoints occur infrequently, he might lose a great deal of progress in the event of a disaster. Although it's better for immersion from the player-centric standpoint, automatic checkpoint saving is inferior to quick-saving. With quick-save, the player always has the option not to save if for some reason he enjoys the risk of having to go back a long way. With automatic checkpoints, he has no choice.
A few games offer optional checkpoint saving in which the player may choose to save or not every time he reaches a checkpoint. This gives him a little more control but still doesn't allow him to save at will, which is preferable.
