Save scumming is a video game term which refers to saving and reloading until you get a favorable outcome. It's a very common tactic in games where you are allowed to save your progress at any point because it allows you to manipulate random events, retry an action until you're successful, or re-fight an enemy until you win on your own terms.
In general, I find save scumming to be a design flaw rather than a feature. Although I prefer to have the option over permadeath, games usually would do better to not allow it at all. In games where save scumming is possible, players often can't resist using it, and this has the downside of replaces the game's fun and challenge with tedium.
As a Game Mechanic
Some games rely on save scumming for the player to progress. For example, in Space Quest I: The Sarien Encounter, the player has to win a slot machine several times in order to get enough money to progress, however, a common slot configuration kills the player, so it is extremely likely the player will die long before winning the necessary amount of money. To continue in the game, the player is expected to save before using the slot machine, reload each time they're killed, and save after each payout. The process is then repeated until the player has enough money.
Saving Yourself Into a Corner
One particularly bad side-effect to save scumming is saving your game in a state when there is no chance of winning. For example, in Doom, you can inadvertently save your game when a rocket is inches from your back, so, every reload will result in being killed again. Games that feature starvation, or similar mechanics, might allow you to save your game far away from any food source with no hope of reaching one before you die, but you won't know it until later in the game.
To avoid having to restart a game due to saving yourself into a corner, you can use multiple save slots across the span of a game. Many games also help prevent this from happening by not allowing you to save when in imminent danger or during a sequence that is guaranteed to end in death. For example, in later Sierra On-Line adventure games, when a death animation begins, the save feature is disabled.
This is not meant to be an exhaustive list, but rather a list of the games that are important to me.
|Castle of the Winds||You can save anywhere at any time, and it's beneficial for saving money when identifying items and avoiding stat loss.|
|Commander Keen 4-6 and Dreams||You can save anywhere at any time.|
|Diablo||You can save anywhere at any time, and it's beneficial for saving money when identifying items and avoiding stat loss.|
|Doom 1-2||You can save anywhere at any time.|
|Half-Life All games||You can save anywhere and the game also frequently auto-saves for you.|
|Space Quest I: The Sarian Encounter||Save scumming is practically necessary at the slot machine.|
|Wolfenstein 3-D||You can save anywhere at any time.|
|Ys III: Wanderers From Ys||You can save anywhere at any time, and with such bad collision detection, it's important to.|
Avoiding Save Scumming
Probably the most common way to avoid save scumming, and the method I most prefer, is to only allow saving at designated checkpoints throughout the game. This retains the game's challenge because players must successfully complete entire segments, but it also doesn't force players to have to complete the entire game in a single sitting. One way this method can be problematic is if the checkpoint can be easily overlooked, say, by obscuring it in a room where the player might miss it. This form of saving is used in games like Final Fantasy VI and Super Metroid.
Don't Allow Saving
This is certainly the easiest way to prevent save scumming, although it is the least desirable. Games like Blaster Master and Bionic Commando will take a beginner several hours to beat, and even a skilled player might spend over an hour on a full play through, but both lack any option for saving. Although saving and passwords were a technical constraint at the time, these days, even short games are expected to save the player's progress.
Reloading Sets You Back
Some games allow you to save at any point, but don't let you restart the game exactly where you saved. For example, in The Legend of Zelda, the player can use the second controller to enter the save menu and save the game at any time allowing you to retain any treasures you've collected. However, saving ends your game and sends you to the game's main menu, and reloading doesn't return you to the exact room where you saved, but rather the starting room of the over world. This forces you to have to journey all the way back to where you left off, a minor punishment for saving. A similar system is used in The 7th Guest: you can save anywhere, and it doesn't hurt you, but reloading starts you back at a hub.
Automatic Save Scumming
Some games make save scumming less appealing by automatically saving the game in regular intervals, and then automatically reloading when the player dies. Games like Shadowgate and Half-Life still allow you to save whenever you want, but since dying always takes you back to the last auto-save, you're never set back very far. Because of this, save scumming isn't really necessary, although it is still beneficial to reload when you take a lot of damage or waste a lot of ammo, but don't die.
With the advent of emulators, save scumming has become possible on pretty much all games. You are able to save the state of the entire video game platform and recall it at any time, usually with the press of a button. Some of the more advanced emulators even let you rewind time by processing the game in reverse. However, I don't think of this as true save scumming because it was never intended, or even conceived of, by the designers.