Meanwhile, the Shilla grand general Kim Yushin (Jung Jin-young) holds back sending his main force to join the advance Allied Army, preferring to deal directly with Yeon Gaesomun's sons than the Chinese.

The Chinese commander Yi launches a full-scale attack on the castle but is beaten back by the Goguryeo secret weapon.

Thingamajig is rewarded by being allowed to marry the brave Goguryeo female warrior, Gap-sun (Sunwoo Sun), against her will.

[1] The box office returns in Korea were not strong which led to Lee Joon-ik announcing his retirement from directing shortly after.

[7] The Los Angeles Times wrote a generally favorable review of Battlefield Heroes, stating that the film "is a handsome, sweeping period picture, a robust, earthy comedy in which the humor, though sometimes labored, results in an amiable if lengthy entertainment".

The review went on to state that an international audience would benefit "by an introductory caption explaining the story set-up in simple terms, as well as some slight trimming throughout".