Well for an idea on Ryo's skills, he was taught mainly in a form of Jiujitsu IIRC, and learns a fair bit of Chinese martial arts techniques in the second game. A better idea of his capabilities can be seen in the QTE scenes rather than the free battles. I'd say the toughest single opponent Ryo had fought in the first game was some Gollum ripoff that had pretty impressive agility (I won't go so far as to say anyone in Shenmue is superehuman though). I'm kinda rusty on the second game's details myself. I can't name all the techniques, but it's around a couple dozen. In one instance, he also managed to battle about five or six dozen thugs with the help of that guy in the suit near the first game's climax.
Just a run-down. Snake is pretty self-explanatory.