Fei Long is a tribute to the Kung Fu movie legend Bruce Lee. Not only do the two look alike and come from the same city, Fei Long also lets out similar battle cries to Lee, and is just as furious and fast a fighter. Also, Fei Long is Chinese (specifically Cantonese, Hong Kong's primary dialect) for "flying dragon", as well as a type of kick; Bruce Lee's Chinese screen name was 李 小龍 (Lee Siu-Long) or "little dragon." The background of Fei Long's fighting venue is based on the Tiger Balm Garden in Hong Kong.
In Fei Long's ending in Super Street Fighter II and Super Street Fighter II Turbo, a movie director approaches Fei Long and tries to convince him into returning to make one more movie, but Fei Long refuses. In the English version, he says that "there could never be another legend like the great one and his son", which has been interpreted by many fans to mean Bruce Lee and his son Brandon who died shortly before Super Street Fighter II was released. This reference is not present in the Japanese version.
A youthful and talented action movie star, Fei Long is the master of Hitenryu Kung Fu. While he fought on the streets to sharpen his skills, he caught the eye of a movie director, who got him into the big times and made him an international sensation.
He made a string of action movies until he participated in the second World Warrior tournament. He realized that he preferred the real thing to the staged, choreographed fight scenes in his movies, and gave up his career and disappeared into the streets.
Rekka Ken motion is a little more forgiving, so it's not as hard to get all 3 in the series.
Buffs
version of Rekkuu Kyaku have additional frames of partial invulnerability, allowing them to go through fireballs at the start.
and Shien Kyaku always knock down and can juggle. Because of this, Rekku Kyaku (juggle) -> Shien Kyaku (juggle) is a new standard combo. The total juggle limit shared by Rekku Kyaku / Shien Kyaku is 4 hits. After 4 juggle hits, it's still possible to juggle with a super.
Rekka Kens travel a little farther.
Super travels farther.
Nerfs
Rekku Kyaku have lower priority on first hit, allowing them to be countered air-to-air a little more easily.
Rekku Kyaku have 5 additional frames of recovery to prevent them from comboing into stand fierce, rekka x 3. Usually leaves Fei Long about neutral on block (time to flame kick!)
Shien Kyaku is no longer safe on block from point-blank range.
Fei Long's head is vulnerable during 4th and 5th hits of the super (and can't go through fireballs during that, but still can during first 3 hits).
Super meter gains slightly reduced on Shien Kyaku and Rekku Kyaku.
Misc
After the last hit of the super, it is not possible to juggle further. (You couldn't anyway in ST due to startup time on Rekku Kyaku, but new juggle properties on Shien Kyaku would have allowed this.)
Fei Long does a short hop, kicking one foot high into the air, and slamming it down, heel first, on to his opponent. In Super Street Fighter II Turbo, pressing forward will make Fei Long hop a short distance.
Engeki Shuu
Distant Attack Kick
Fei Long performs an even longer jump, leading again with a kick. If Fei Long connects with this move, it hits twice. It closes a bit of distance between him and his opponent, but it is a bit slow.
Rekka Ken
Conflageration Fist
The Rekka Ken is actually a three part move. The motion must be entered three times in rapid succession for Fei Long to perform the entire move. When he does, he rushes forward with three unique punching strikes. Given the control that the player has over this move, Fei Long can execute as many parts of the move as he likes, allowing him to change up his strategy and swap the second or third strike with an alternate attack.
Shien Kyaku
Kindling Blaze Kick
Fei Long focuses all of his fighting ki into his foot, and revolves it around his body, leaping upwards in the final moments. He achieves enough speed to ignite his leg in a field of fire, burning any opponent who is struck by this attack.
Rekkuu Kyaku
Violent Air Kick
In Super Street Fighter II Turbo, Fei Long gains the ability to perform a long range leap kick. This leap can send Fei Long across the most of the screen, and clears many low flying projectile attacks. Best when used as a projectile counter.
Rekka Shin Ken
True Conflageration Fist
Fei Long's super move is a powered up version of the Rekka Ken. Fei Long stores all of his energy up, and releases it in a blinding flash of five rapid strikes. The move causes Fei Long to rush forward quite a bit, but he is usually safe even if the move is blocked.
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version of Rekkuu Kyaku have additional frames of partial invulnerability, allowing them to go through fireballs at the start.
and 
Shien Kyaku always knock down and can juggle. Because of this, Rekku Kyaku (juggle) -> Shien Kyaku (juggle) is a new standard combo. The total juggle limit shared by Rekku Kyaku / Shien Kyaku is 4 hits. After 4 juggle hits, it's still possible to juggle with a super.
or 
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or 
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(perform 3 times)
+
close, 
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