Kamehameha

Kamehameha is 's and Super Saiyan Goku's standard special move in Super Smash Flash 2.

Overview
When performed, Goku cups his hands to his side and concentrates his ki energy into a single ball-shaped point between them. Holding the special input charges the energy, and when the released, he then thrusts his hands forward to shoot it out in a streaming beam of energy. Kamehameha goes through four states of charge, with the stored ball of energy flashing and growing in size once every second, though after the third stage it takes two seconds to reach the fourth, full charge, which maintains a constant size and glows brighter. With each ascending charge, the beam becomes larger, travels more range, and deals more damage and knockback to opponents hit. At its lowest charge, the beam is weak and travels very little range, but at full charge, it is much more powerful and travels a great distance.

When being charged in midair, the move dramatically slows Goku's descent, and when released in midair, it pushes him back, with higher charges pushing him back more. Additionally, Goku has the ability to turn the other direction when releasing the beam in midair.

Kaiō-ken Kamehameha
Kaiō-ken Goku's version of the move is called Kaiō-ken Kamehameha. This version of the move charges twice as fast as the regular version and is more powerful overall. This move can stall the duration of Kaiō-ken to infinite if the player doesn't release it but at the sake of Goku's percentage.

Super Kamehameha
Super Saiyan Goku's version of the move is called Super Kamehameha. This version of the move is dramatically more powerful than the regular version and has a longer range. When Super Saiyan Goku releases a fully charged Super Kamehameha, the attack becomes known as the True Kamehameha, turning Goku into his Super Saiyan 3 form and releasing a giant wave of energy.

Origin
The Kamehameha is Goku's signature move in the Dragon Ball franchise. It is the first Ki-based attack to be introduced in the franchise and continues to be the most commonly used, due to being not only iconic but also simple and practical. Goku's martial arts teacher, Master Roshi, is the first person on Earth to discover it, and it had allegedly taken him fifty years to develop. Goku was not taught it directly, but first learns it upon seeing Master Roshi perform it once in order to put out the fire on a burning mountain (though destroying the mountain entirely in the process).

Even in the earliest points of the series, long before large-scale destruction was a common occurrence, its destructive power and reach were supernatural in magnitude. Along with destroying the aforementioned mountain, it was also used to destroy Earth's moon to stop Goku, rampaging as a great ape, from destroying the World Tournament.

Being such a common attack, it was natural for variations to spring up as the series went on. Out of the variants that appear in SSF2, the Super Kamehameha is first used against Piccolo, the Kaiō-Ken Kamehameha was used notably against Vegeta and Frieza, and the True Kamehameha was used against Majin Buu. All variants tend to appear as separate attacks from each other in the video game adaptations.

Trivia

 * In its first appearance in v0.7 of the demo, the fully-charged Kamehameha was the single most damaging attack — barring Final Smashes — in any version of SSF2, dealing 51% damage. Its power was significantly reduced in later versions.
 * Prior to v0.9b, the interior of the stored energy would flash at full charge. While this trait has been removed from the regular version, it still occurs with Kaiō-ken Kamehameha and Super Kamehameha.
 * The Kaiō-Ken Kamehameha went through a number of drastic changes between versions. In v0.8a, Goku skipped the charge entirely, instead immediately releasing a stage 3 Kamehameha. In v0.8b, the charging returned, but it is quite difficult to fully charge as the Kaiō-Ken would most likely run out an instant after stage 3 began, interrupting it.