Over at Gamedevleague, Jamie has written a post about games breaking the fourth wall, and how it tends to spoil his experience. (Breaking the fourth wall is a term from theater. The actors can pretend there is a fourth, invisible wall between them and the audience, or they can 'break' it by talking directly to the audience.)
Suspension of disbelief is subtle and complicated. Jamie mentions two cases of breaking the fourth wall he doesn't like. The first is games referencing the fact that they are a computer game (and I mean games that make some effort to make the player believe in a fictional world - not Tetris). Metal Gear Solid 1 did this: what I didn't know was that Metal Gear Solid 2 and Max Payne did this as well. Jamie thinks this happens when designers are too pretentious, and he's got a point. On the other hand, I encourage designers to become more sophisticated and use more fancy tricks from traditional storytelling. The Metal Gear Solid series and Max Payne series, whatever their faults, have definitely shown that you can achieve both commercial and critical success doing this.
The audience's ability to suspend disbelief is based on an unspoken set of rules about how a medium functions. The audience comes in with certain expectations (e.g. from other, similar, works). As an artist, you can bend or break these rules, but to do so consciously and effectively, you must first be aware of them. When certain rules have become very familiar to your audience, you can start playing around with them without causing confusion. Watching movies has become such an unconscious skill that we have no problem when Brad Pitt talks directly to the audience in Fight Club - especially since the filmmakers have already subtly communicated that they are playing by a different set of rules beforehand, through the use of voice-overs, camera work and special effects. Movies, novels, etc. have a learning curve, just like games.
There's an additional aspect in games. Great designers know how to create a feeling of safety in the player's mind. At some point in Chrono Trigger, all of your weapons are taken away, yet I wasn't scared that I might end up getting screwed, that all the time I had invested until then might end up being for nothing, because up to that point in time I had not experienced any bugs or design errors, and I had consistently been entertained. As I expected, I got all my precious objects back at some point.
A game that referenced its videogameness without shaking the foundations of suspension of disbelief was Lucasarts' Day of the Tentacle, where one player-controlled character, after having just done something pretty awful, mentioned that he sometimes felt as if he was the plaything of a malignant force. In a recent discussion on notable quotes in games, someone mentioned that when you saved your game in Planetfall while Floyd was with you, you'd get:
Floyd's eyes light up. "Oh boy! Are we gonna try something dangerous now?"That's Steve Meretzky for you. Note how the unifying element in the last two examples is humor. As Mark Barrett once pointed out to me, you can get away with an awful lot if you make people laugh.
The other case of breaking the fourth wall Jamie mentions is in-game characters referencing, say, controller buttons. I am in two minds about this. On the one hand, the wrong use of point of view in in-game text is definitely a problem. (For instance, in KOTOR it's pretty screwed up, even beyond the problems that RPGs can create.) But in Zelda: The Wind Waker I wasn't disturbed by characters saying to me which button to use for what. In my opinion, this is because my expectations of the complexity of Zelda's fictional world are not that high. It's obviously a children's book world, with cartoon visuals, cartoon physics, cartoon logic, and cartoon characters. (I mean this in a good way!) Therefore, and because I am consistently entertained, I don't mind it when characters give me very direct hints and reference controller buttons - something which I would find bothersome in games with a more realistic setting.
Setting up, maintaining, and manipulating the unspoken rules of a game in order to create emotional effects is perhaps both the subtlest and the most crucial aspect of game design. This is where a turn of phrase or a judicious choice of color can make a huge difference, where there are no easy rules because everything is interconnected and every element must be designed to work well together, no matter how they work individually.