Following a short period of training (during which Barry discovers that the duel was a set-up and the Nora has actually married Quin) he is shipped to the battlefields of France. The romantic ideals of youth, regarding honour and valour in warfare, are quickly stripped from his manner to leave a frightened young man. The senseless waste of life, where British soldiers march into the roaring French guns without response, convinces Barry that desertion is the key. When the chance comes (in a rather singular incident) Barry returns to a life of travelling, this time in the disguise of a British officer. Looking for a way to return home Barry heads for neutral Belgium, using his stolen identity (luckily news didn't travel very quickly in those days). His luck is still bad though when a clever Prussian officer, Captain Potzdorf (Hardy Krüger), sees through the smoke-screen and presses him into their army (which is even worse that the British one). Forced to mix with the scum and dregs of Europe Barry hits rock-bottom in his fortunes.
Experience, cunning and a burning desire to be a gentleman soon propel Barry upwards when he achieves favour with Captain Potzdorf. Offered the chance to escape from the army, if only he'll do a little spying, Barry seizes the opportunity. When his target, the inveterate gambler and womaniser The Chevalier (Patrick Magee) turns out to be Irish too then Barry is quick to turn double-agent. Playing his Prussian masters, Barry is able to protect Chevalier and eventually flee with him, ensuring his place at the best gambling tables of Europe. As a team Chevalier and Barry tour the continent making money and acquaintances, which is like a dream come true for Barry. Having reached a state of pure cynicism he decides that he needs a rich and titled wife, which will make his ascent complete. Barry's luck runs true when Sir Charles Lyndon (Frank Middlemass), a near-death English lord, visits with Lady Lyndon (Marisa Berenson), a beautiful and young wife. When Sir Lyndon drops dead Barry is wooing Lady Lyndon in a flash, which leads to their eventual marriage. However, a storm is gathering on the horizon in the form of Lord Bullington (Leon Vitali), the son of Sir Lyndon and passionate hater of Barry.
Stanley Kubrick once again attempts film-making on an epic scale, attempting to cover a whole life, and mostly succeeds with Barry Lyndon. The tale of one mans roller-coaster life is both impressive and engrossing, covering the way in which a fortune can be made then dissipated through negligence. However, for a film in which so much has to be packed (which means that many characters are only seen briefly) the overall pace is very slow and measured. This is fine for certain scenes, such as pistol duels where the tension can be racked up, while at other times this allows the attention to wander. This tendency isn't aided by the flat performance of O'Neal, appearing most of the time with a blank, expressionless face (only rarely does real emotion seem to occur within). Given that Barry is central to the movie this is perhaps a regrettable casting choice, although the remaining characters are fine. The result of the ensemble acting is that it's difficult to retain any emotion for the characters, instead feeling that their misfortunes are purely their own fault and therefore quite just.
Where the film really takes off is in the fabulous photography, particularly the indoor scenes. Kubrick wanted to use only natural lighting and, using special lenses, candlelight. The result is an exceptionally smooth and rich look, particularly in the colours of the clothing, which is intuitively right (rather than being bleached out with artificial illumination). Windows take on an almost fluorescent character, contrasting with the gloom of the unlit room corners (which show just how difficult life was with candles). The score is also reminiscent of the period, being composed of classical melodies which have been re-interpreted. Additional narration, to explain external details, is included and rather useful. Ultimately, Barry Lyndon fails to constitute an excellent film by virtue of its characters, even though the underlying story is strong and exciting.