The body has ordered Eidos not to print or broadcast the ads again, after upholding 26 complaints and calling the promotion 'graphic' and 'shocking'.
One press ad shows a gagged woman, crying and having her head held back by one of the pair. It was printed over a double-page spread in Edge, with a second version appearing in Total Film magazine.
The ASA said: 'The portrayal of violence it contained, with particular regard to the female hostage, was graphic and too shocking to be seen in an untargeted medium.'
Another Kane & Lynch poster held a quote from the Official Xbox 360 Magazine stating, 'Grittier and nastier in tone than anything you've seen before, the violence here is visceral, brutal and very, very real'.
The ASA said this version was 'likely to be seen as condoning and glorifying real violence', and was also irresponsible and 'likely to cause serious or widespread offence'.
The body ruled that both press ads were 'graphic and too shocking to be seen in any medium' and said they breached its code on responsible advertising, decency, violence and antisocial behaviour.
Complaints against a TV ad for the game were also upheld, with the ASA concluding that it breached its code on harm and offence, violence and cruelty and personal distress.
The ASA added: 'A "crunch" sound was heard as the butt of a rifle was brought down on what was suggested to be a victim's head and another in which a man with a bloodied face appeared to have his throat cut; which we considered were likely to cause offense and distress to viewers despite the animated treatment.'
In its defence, Eidos said the poster image was intended to be 'cinematic' but it was not their intention to cause offence. The publisher also pointed out that, although the print ad portrayed a kidnap scene from the game, the woman was unharmed despite the mouth gag.
The firm said the TV ad was also designed to be cinematic and because of the subject matter of the game, was "not ... overly violent".
Channel 4 and Channel Five, which broadcast the TV ad, apologised for any distress caused.