In those days, we didn't have the isolation or a hell of a lot of instant replay, so you didn't get to catch the play of offensive linemen, at least i didn't. They also had 4 TV networks, mostly. I knew, of course, that Hanna was the best (reputation), but never really knew why.
Toward the end of his career, they had a special on him where they did isolate him on a number of plays. i didn't see the play I remember in that clip, but I'll never forget it. The RB was behind Hannah who had pulled and the defense was stringing it out. One defender was running toward the sideline and the contain guy was leaning back, as it looked like they might cut it between them.
I wondered which way Hannah would play it and who he would block, when he feinted slightly, then stuck out both elbows and pancaked them simultaneously, like a cartoon. The running back was so shocked, he almost tripped over his own feet, but recovered and trotted down the now open field, trying not to trip on the bodies. OK, now i understand.