Gi,
Our sytle of hapkido seems to me to be pretty similar to the "hard" styles of aikido.
We are a small kwan, only one dojang in Korea and fewer than ten in the States. Also, our style of hapkido differs significantly from most of modern hapkido, because we only do the techniques that Choi Yong Sul, the founder, taught the head of our kwan, Master Lim Hyun Su. Nearly all modern kwans can trace their lineage back to Master Ji Han Jae, an early student of Choi who, with a colleague, added the elaborate kicking repertoire to Choi's "yawara" base. Ji also added meditation and philosophy components to form the art he calls Sin Moo hapkido.
Ji calls himself the founder of hapkido, but to debate whether Ji or Choi is the founder of the art is to fall into a semantic abyss, because it depends on what one means by "hapkido".
Most people think of the elabortekicking when they think of hapkido, and that is generally accurate. But not in our style. We have ten basic kicks, nine of which are to targets below the waist. These are the basic kicks that Choi taught Master Lim. Choi taught that to kick high in a fight is dangerous, because it puts you off balance and makes you vulnerable to counters.
As far as I know, the only other kwan that teaches only what Choi taught (in other words, that has not added Ji's kicking, meditation, philosophy, etc. to its curriculum) is a group called the Yong Sul Kwan, led by Master Kim Yun Sang. Both Lim and Kim were 9th dans under Choi - two of the four he promoted to that rank during his life.
Many of our higher-level techniques strongly resemble corresponding Daito-ryu aikijujutsu techniques, which is why I believe (in spite of the ongoing absence of documentary evidence) that Choi did indeed learn Daito-ryu during the thirty or so years he spend in Japan before repatriating to Korea after WW2.
In fact, a number of the techniques in that Yoshinkan clip look a lot like some of our techniques. Not surprising, since they probably share a common source.
Hope this helps... please let me know if you'd like to know more.