Cage

A GI in Vietnam saves his buddys life, but in the process is shot in the head. The injury results in brain damage to the point where he basically has a childs brain in a (very large) mans body. When they get out of the Marine Corps, the two open up a bar together, but some local gangsters make things tough for them after they refuse to take part in brutal cage matches where fighters battle to the point of serious injury and/or death.