Looking back now, it’s conceivable that the casting decisions James Clavell envisioned could function effectively; however, in 1971, having Omar Sharif portray the German character "Vogel" alongside Michael Caine as a “Captain” who isn't entirely believable places a significant strain on believability. Including Nigel Davenport as "Gruber," an overly stereotypical Englishman, and Brian Blessed in the role of “Korski” only compounds this problem. While the production values are high, with meticulous detail and a powerful score by John Barry, that’s essentially what you end up with. The narrative unfolds against the backdrop of the 30 Years' War—an event perhaps unfamiliar to many Germans, let alone people elsewhere—and possesses elements characteristic of an exciting action film. Armies, villagers, even individuals clash over the significance of their churches – a conflict between Protestant and Catholic beliefs – representing a struggle between traditions that arguably ought to have been considerably more captivating. Clavell’s adaptation of his novel maintains a brisk pace and delivers plenty of action; it simply fails to ignite any real spark. Running for slightly more than two hours, the film feels protracted, with the major actors seeming miscast. They never quite manage to work together effectively. It's unfortunate because the subject matter—religious intolerance from every perspective—lends itself well to a compelling movie. This one, though, falls short of that potential.

Source on TMDB