Ryo Sakazaki is originally from the game Art of Fighting. Ryo in CvS2 is loosely based off the KoF version of his character and whilst appearing to have a similar moveset to Ryu and Ken his actual gameplay style has more in common with Guile.
Overhead chop f+mp
Zanretsu Ken: f, b, f + P
Hien Shippuu Kyaku Charge db, f+K
Kououken qcf+P (also in air)
Mouko Raishin Setsu (?)
Kyokugenryuu Renbuken hcb+P
Haou Shokoken f, hcf+P
Ryuko Ranbu qcf, hcb+P
Tenchi Hakouken qcf, qcf+P
Ryo is best as a ratio 1 or 2 character.
To play Ryo effectively one must keep around medium distance agaianst the opponent using fireballs to interrupt movements and doing low chain combos into more fireballs e.g c.lp,c.lk,c.mk fireball or c.mp fireball.
His crouching and standing medium punch has excellent priority and can be linked into moves.
The jumping fireball should only be used while jumping forward as after the fireball is cast - it delays Ryo landing on the ground, its quite good when you predict your opponent is going for some obvious anti air attack and you can
Zannretsuken can be used to catch people who are too obvious with their rolls or jumps but otherwise shouldn't be used.
His dragon punch has average to low damage and in a lot of ways is like super turbo guile's flash kick, it comes out quick and finishes quick so its not entirely ideal as an anti air, his standing heavy kick is far better as a anti air. It's good if you want to land a knock down, the light punch version should be the only version used.
Kyokugenryuu Renbuken can be super jump canceled and most players who do this follow up with jumping heavy punch.