Some scripted sequences are merely used to play short cut scenes which the player has little control of. However, they are commonly used in games such as Half-Life or Call of Duty to bring in new enemies or challenges to the player in a seemingly surprising manner while they are still playing. They can also present further plot points without requiring the player to take a break by watching a cut scene. The intended results of this style of presentation is to increase immersion and to maintain a smoothly-flowing experience that keeps the player's interest.
However, games such as Call of Duty have been particularly criticised for a reliance on these sequences, as many feel they tend to guide a player through a game by the invisible hand of the developers. Also, the use of scripted sequences tends to diminish replay value as the surprise effect is negated upon subsequent play-throughs.