Nice to see the contrast of his style when he was young for comparison. Some of those falls may look faked, but there are points where the joints are under such pressure you risk injury if you don't go over. Not to scare people off from aikido, I'm sure O-sensei knew his students and just how much they could handle. In a good dojo you are always aware of how hard to push your partners. A beginner will never be asked to take a difficult advanced breakfall. Once you've been at it for awhile, it's a blast getting thrown around the dojo, and pinned in excruciating ways. Relaxing into the pins as the pressure increases is a nice way to get more flexible.