The Guns of Navarone (1961)
This moral-soaked wartime drama believes itself to be a tale of heroics filled with some human and ethic truths. Unfortunately, it is mostly painfully staged gabble wrapped in banal, unrealistic WWII action. MacLean adaptations range from the brilliant to the mediocre, but rarely do they lack suspense as much as The Guns of Navarone does. The reason isn't the story itself, or the payoff for that matter, but rather the poor directing and acting leading up to it.
Director Thompson's pacing leaves a lot to be desired, dwelling for minutes at parentheses and over-dramatized interpersonal segments before rushing through important strategic aspects of the mission in question - presumably for lack of the shrewdness and knowledge needed to take us through it decently. And as Thompson stumbles ahead, the acting worsens proportionally. Peck and Niven both pull themselves through embarrasing emotional outbursts that don't have the needed dramatic foundation, while every actor in non-anglo-saxon parts are helpless against thoroughly stereotyped characterizations. In the first couple of decades after the war, few films could boast anything resembling objectivity or depth when it came to the depiction of the "bad guys" in WWII, but in The Guns of Navarone, these characters are more unauthentic and biased than you'll find anywhere. If you want to see a good rendition of a MacLean WWII novel, choose Where Eagles Dare instead. It has the same dramatic structure but vastly superior execution.