Suspension of disbelief

The term Suspension of Disbelief (SoD) is a phenomenon present in all media in where the audience/player are willing to suspend there knowledge of the real world for the sake of entertainment and with knowledge of the limitations of the media.
SoD is what makes the audience "buy" that James Bond can take 20 blows to the face without even getting a nose bleed.

In the Wikipedia article on the subject many game conventions are given as clear examples of SoD. Like the player dying if falling into water - even though it seems plausible that the character (a heroic adult) would be able to swim.

There are however many things that will push the limit of how much an audience are willing to suspend their disbelief.

For example the fictional element called "Breaking the Fourth Wall (an invisible wall separating actor from audience)" often brakes the spell for an audience. These are the times when a character in a film or play directly addresses the audience, where the characters displays signs of knowing that they are in a work of fiction or reference something that they wouldn't know given the fictional world they exist in. In games, having characters referring to save points or controller buttons would be a clear example of this kind of brake. Even though it could be successfully employed if used conscientiously in the tongue-in-cheek manner of the Metal Gear Solid series (or more recently, the game Eat Lead).

A game always balance on what Murray calls "the enchanted threshold". Player's will always be willing to suspend their disbelieves (forsaking their primary framework for the fictional framework of the game), but will always be sensitive to brakes in the "fourth wall", especially if the game is attempting to portray a realistic virtual world.