Many a game maker loves to think that gamers play their game over and over again. Despite honest efforts to create "replay value", we know it’s not true: after the players complete the challenge that the game represents, most of the magic is gone and the will to play is very diminished. Having gamers replay the game is very interesting. It is always flattering, but it goes beyond that: replayers will pay more attention to the details of a game, they are more likely to share their passion online. And because replaying is a much more voluntary action than playing the first time, this commits the player towards the game: chances are that a replayer will be interested in other titles of the series, or, failing that, future titles of the same developer/publisher.
All of this to say that replaying is definitely something to encourage among your players. Yet, surprisingly, this is very seldom the case.
What does a replayer want?
to relive the excitement of the game, especially the parts they liked best.
A more difficult challenge. After playing the game once, the replayer will be more expert at the game mechanics, they won’t be surprised by the layout of the levels, etc.
A slightly different game. If anything changes during the second game, such as the character’s looks, parts of the story, etc. this will act as incentive for replayers.
The possibility to carry on developping what they built during their first game ... or not. (experience, money, weapons, awards, ...)
What do they not want?
to have to go through the same mandatory, lengthy game parts (cutscenes come to mind).
to have to spend hours of re-gaming just to relive one moment of the game they like best.
Modern games are often segmented in a sensible way. Instead of playing the game from beginning to end, having to load a saved game if "killed", players now have the habit of enjoying the game through a succession of scenes in a more or less seamless succession. That segmentation can be:
formal: these scenes are called "level" or "mission" or "chapter" or whatever,
informal: you never see a checkpoint until you need it, or
anything in between.
Instead of letting the player progress unless their character is "killed", such games allow more flexibility in the game flow progress: if the player fails to fulfill objectives, they lose and have to start again from the beginning of the scene (checkpoint).
Excuses to prevent users from selecting what part to replay
With more and more games following that paradigm, it’s hard to understand why so few game authors let replayers chose, with more or less precision, which scene they want to replay. Letting the player replay nothing but the full game is excusable for smaller, shorter games which can be cleared in a couple of hours by non-fanatic players. Other games should let users choose what part they want to replay, just like DVDs let viewers see movies by chapter.
There are three (wrong) reasons not to do this, so let’s deconsruct them.
"level selection has been a popular cheat mode for ages, so level selection is cheating, and it’s wrong to allow this". But you don’t want to build your game on tradition, rather, on what’s working or not today. In my book, a player who has beaten a game has fully deserved the right to replay it in the order they see fit. And as a side comment, cheat codes should not be taboo.
"isn’t what saved games are for? If a player want to replay a scene, why not save a game right before?". Saved games are rather tools to help the player progress in the game. It is the right of players to use them as they see fit - only keep one save file throughout the game, save every 5 minutes on a different location, etc. It is the job of the game author to make sure that the player can have a satisfying replay experience, they should not rely on the player to save games in a specific fashion. Besides, as players discover the game for the first time, how could they tell that what will be their favorite scene is coming up next and that they should save now if they want to replay it later?
"OK, let’s assume the player can replay individual scenes. But in what state? If they are too powerful, or have access to specific abilities, the gameplay of the scene will be ruined". If they are empty-handed, the scene could be insanely difficult. Those continuity issues are probably the hardest to resolve. But again, this is rather a pre-conceptions rather than an actual issue. There’s nothing really wrong in letting a player with a character fully powered-up replay a scene that they have liked. The worst that could happen is that it could cause confusion for the player. This is why in Zelda: the Wind Waker, towards the end of the game, when the player faces bosses that they defeated early in the game for the second time, their inventory is limited to what they had back then , so they won’t be tempted to try things that don’t work. An alternative is to predict the "optimal" state of the characters at the beginning of the scene (inventory, level, abilities, etc. ). This requires more scripting but can lead to interesting results. Finally, for some games, it may be possible to let the players relive a game scene with "blank" characters, with no equipment, no acquired power, etc. If the segmentation of game scenes is well done, the game will never let a player completely helpless so they could pick up a few items and be strong enough for the challenge ahead.
Replayability practices
FFX-2 is probably one of the champions of replayability. Even if the game only allows to replay it from the beginning, it is so modular that players can reach the part they like very shortly, without having to go through tedious gameplay. And yes, they can skip all cutscenes.
Games like Tony Hawk Pro Skateboarding or Rogue Leader, which are arranged in episodes, let players replay any level they have unlocked at all time. Meanwhile, the player becomes more and more powerful: by buying new skateboard equipment, or buy finding secret power-up for spaceships scattered through the levels and unlocking new ships. And yes, they do have the possibility to replay earlier levels with stronger characters/ships.
Metal Gear Solid, while divided in missions, doesn’t allow to replay it at this level. That is too bad, because the game is fairly long. The same can be said of Grand Theft Auto series. Once a mission is accepted and passed, the only way to replay it is to beat the game, then work your way to unlock that mission, which can take up to 30 hours.
Resident Evil 4 has some interesting special modes, including the movie browser that let the player view all of the cutscenes. But it lacks the possiblity to replay individual chapters, which is too bad since contrary to the earlier episodes of the series, this one is much more segmented than they were. May be for Resident Evil 5?