Having attended General Eisenhower's final briefing on the upcoming Normandy landings, U.S. Army major Jeff Pike is sent to Lisbon, Portugal on June 1, 1944 to meet an informant to confirm that the Nazis still expect the invasion at the Pas de Calais.

He advises Pike that his blocked memories have always resurfaced, helped along by a therapy of remembering events prior to Lisbon and then pushing forward into the blank period.

Schack is sure that the invasion will occur at the Pas de Calais, but Gerber sets the clock forward so that Pike and Anna believe that it is the morning of June 5 and then states that the Germans have been surprised at Normandy.

Schack arrives at the minister's house after Furzen and the couple have left for the border, but he recognizes Anna's ring on Elsa's finger and forces her to reveal where they have gone.

[6] The New Yorker called the film an "ingenious thriller" and praised Garner, Saint, and Taylor for being "plausible in highly implausible roles".

[7] Kate Cameron of the New York Daily News gave the film a full four-star rating and said that "the plot is cleverly and believably worked out on the screen, and the excitement of the intelligence operation is augmented by the limited time the Germans have at their disposal to brainwash their prisoner into believing he has had a form of amnesia that has blotted out six years of his life.

"[8] A user of the Mae Tinee pseudonym wrote that "unfortunately, the plot is almost too complicated, with Eva Marie Saint, a former inmate of a concentration camp, and Rod Taylor, as the psychiatrist, battling their better instincts; and a greedy traitor clowning clumsily in the finale.

"[10] Henry T. Murdock of The Philadelphia Inquirer said that "the clever Perlberg-Seaton team plays fair with its audience and plants its major clue right in front.

[11] Sandra Saunders wrote in the Philadelphia Daily News that "the full impact of the bizarre situation is weakened by the fact that the audience is in on all the details from the beginning.

However, tension and suspense mount steadily as Garner innocently falls into the trap, accidentally discovers he's been duped and then launches a "game" of his own to befuddle the Nazis.

"[12] Louis Cook of the Detroit Free Press said that "after awhile '36 Hours' begins telegraphing its minutes but even then it maintains a certain interest.

"[14] Louis R. Cedrone Jr. wrote in The Evening Sun of Baltimore, that "when it is about half over and the gimmick has run its course, '36 Hours' becomes Just another spy drama, but a good enough one as they go.

"[15] Myles Standish, in the St. Louis Post-Dispatch, called the film "a bizarre and intriguing [spy melodrama], with a fantastic espionage plot and an exciting duel of wits.

[16] Stanley Eichelbaum of the San Francisco Examiner described 36 Hours as "a mighty tense and exciting suspense film",[17] while Marjorie Adams of The Boston Globe said it "lives up to what most people expect of the men who made 'Counterfeit Traitor' and 'The Bridges of Toko-Ri' in that it deals with fast action, intriguing characterization and a logical conclusion.

"[23] Connie Richards of The Commercial Appeal wrote that the film's premise "may sound flimsy on paper, but it is terrifyingly real on the screen with the help of James Garner as the bewildered officer, Rod Taylor as an American-born Nazi psychiatrist and Eva Marie [Saint] as an effectively cool accomplice.

[27] William J. Nazzaro of The Arizona Republic called the film "a neat, well-acted, melodrama dealing with espionage in the days before the Allied invasion of Europe in 1941.

Though this Perlberg-Seaton production makes the usual concessions to popular taste, '36 Hours' should prove entertaining to anyone who craves a fair amount of action for his film fare.

[29] Giles M. Fowler of The Kansas City Star, called the film "an absorbing and well-crafted bit of nonsense, guaranteed to keep the most, skeptical viewer on tenterhooks".

[32] George Bourke of The Miami Herald said that the film "ticks off the minutes at a fascinating pace in an espionage suspense drama with a unique twist".

[34] In the opinion of The New York Times critic Bosley Crowther, "What is annoying about this picture is that the set-up for pulling off the plot is just too slick and artificial, too patly and elaborately contrived.

Even though Mr. Seaton has done a thorough and careful job of staging this massive deception and has got his able cast to play it with reasonable assurance, it has such a synthetic look and, indeed, the idea is so theatrical that the whole thing rings curiously false.

"[36] In Baltimore, Maryland, R.H. Gardner wrote in The Sun that "the first half of '36 Hours' is such stimulating stuff that one can't help resenting script writer George Seaton's inability to keep his story from deteriorating into a standard spy-melodrama.

But the idea runs out of gas soon, and "36 Hours" turns into a dull and predictable melodrama populated by all those grim, stocky hood types who were playing Nazis in the flicks 20 years ago.

Seaton's story, during Act I, stands back and takes quick, admiring glances at the efficiency of the Nazi intelligence operation, of their plans to convince Pike the war has ended and get him to talk about what was to come off on D-Day.

Then, abruptly, the taut stack of cards collapses in a string of cliche dialog and characterization that renders '36 Hours' just so-so from an over-all view.

"[40] Jack Holley of the Evening World-Herald in Omaha, Nebraska said that "the set-up for the plot is too artificial and too contrived" and that "suspense would have been better maintained if the staff and patients had made occasional slips, especially Rod Taylor, who is overly all-American as the German doctor who dreamed up the scheme.

"[42] Dick Richards of the Daily Mirror said that "the film '36 Hours' (Empire, A) is a tense game of cat-and-mouse that may have some flaws for those who were mixed up with wartime Army Intelligence.