"Suddenly" stands next to greatness without touching it. The script is tight and fast-moving, though the setups are a little too obvious and the payoffs a little too predictable, and the storytelling sometimes feels rushed. (The final scene, seemingly meant to "come full circle," is incredibly contrived, as well.)

Social and psychological issues are subservient to the plot, and are dealt with superfically. While the film's attitudes can seem daring today, it's worth keeping in mind that its message (that weapons are morally neutral tools, which good people can use for good purposes) was as politically correct in 1954 as liberal "guns are bad" rhetoric is now, and in that context a mother's objection to her child playing with cap guns or seeing war movies can be portrayed as a neurosis.

Enough with the social implications; what about the acting? It's mostly good. Sinatra has the perfect look for his character, an ex-soldier and sadistic killer for hire, and his performance is an unnerving combination of slow-burn and sudden snap. Nancy Gates (as the neurotic mother) gives an intelligent, emotionally plausible performance. James Gleason is a stereotypical Gruff Old Man. Kim Charney, like many child actors who find themselves in major roles, subsides on cuteness and pathos while delivering his lines with a grating sincerity. But it's Sterling Hayden who almost sinks it all. He isn't merely wooden -- he has termites. His appearance (he looks like a rough draft of James Stewart) and his ridiculously deep voice don't help, but his worst flaw is that he apparently cannot act.

Now, Maxine Cooper in the excellent "Kiss Me Deadly" was at least as bad, but "Kiss Me Deadly" is a more resilient script. Cooper said her lines badly, but they were still good lines; Hayden blunders through a part even a good actor would have trouble with. A heavy-handed flirtation is only the start; he goes on to portray toughness, well-intentioned deviousness, and official business without once changing his tone of voice.

Reading over this, I fear I have portrayed "Suddenly" too negatively. It's really a fairly enjoyable film of average quality. Sinatra's intense, nuanced performance easily counterbalances Hayden, and the plot, despite some implausibility, is pleasantly tense. A remake would be interesting; until one comes along, this one may be worth a look.