Street Fighter Alpha/Gameplay

Controls
One player may compete against the computer, or two players may simultaneously compete against each other. Each player has an 8-way joystick and 6 buttons.

Buttons
The buttons on the arcade are typically laid out in the following fashion: The L, M, and H stands for light, medium, and hard respectively. In general, light attacks are less powerful and faster, and hard attacks are more powerful but slower, with medium attacks in between.

Joystick
The joystick works intuitively in that pressing left will generally move your character left, and pressing right will generally move your character right. But it is more important to think in terms of relative direction. For this reason, all instructions are given with respect to forward and backward since the left and right directions change purpose when your character switches directions.
 * If your character is facing to the right, then pressing left on the joystick means backward, and pressing right on the joystick means forward.
 * If your character is facing to the left, then pressing left on the joystick means forward, and pressing right on the joystick means backward.

The following directions assume that your character is facing right, the starting direction of every fight for player one, who begins on the left side:

Rules
Each battle consists of best-of-three round match between you and your opponent. At the start of each round, both player's life or health bars are full. The first player to drive the other player's health bar to zero wins the round. The first player to win two total rounds wins the match and moves on to the next opponent. If a single player loses to the computer, the game is over and the player must continue to rematch the recent opponent.

Attacking
To win a round, the player must use his or her character's attack moves to damage the opponent, and block or dodge the opponent's attacks. Each player may attack from a standing or crouching position, or they may jump in to the air and attack. To attack from a standing position, press any single attack button. To attack from a crouching position, pull the joystick in a downward direction (including both diagonals) and press any single attack button. To attack from the air, direct your character to jump straight up, or jump in a diagonal position, and press any single attack button in mid-air.

Blocking
To block an attack, a player must push backwards on the joystick when the opponent attacks (otherwise, pressing back on the joystick moves the player away from the opponent.) Blocking can be done standing which blocks middle and high attacks, as well as attacks in the air, but does not block attacks which are low to the ground. Blocking can also be down crouching by pressing the joystick diagonally down and back. A Crouching block will successfully block low and middle attacks. High attacks will usually go over your character's head if they are crouching, but a crouching block does not defend against air attacks or attacks known as overhead attacks which start high and travel down (such as Ken's axe kick). Street Fighter Alpha incorporates the concept of air-blocking which is the blocking of attacks while in mid-air. As long as you have not initiated an attack, you may hold back on the joystick while jumping through the air to avoid damage.

Special Attacks
In addition to normal attacks there are attacks known as command moves and special moves. Command moves are special combinations of a joystick direction and a particular attack button that produces a different attack than when the button is pressed alone. A special move is a move that requires a more complicated joystick motion and an attack button to perform. For example, Ken and Ryu's fireball attack, called Hadouken, is performed by sliding the joystick in a circular sweeping motion from down to forward, and finished off with any punch button. In this example, the strength of the punch button used happens to dictate the speed at which Ken and Ryu's fireball attack travels across the screen. Special attacks can be blocked like any other attack, but they do what's known as "tick damage." That is, even when blocked, they removed a single hit point from your health bar. Most special moves have a pause associated with them that leave you vulnerable to attack if you miss the opponent, or "whiff".

Super Moves
In addition to the health bar shown at the top of the screen, each player has a super meter at the bottom. As the player attacks and damages the opponent, and as the player takes damage from the opponent, the super meter fills up incrementally. The super meter fills up to three distinct levels of power. A player may execute a Super Move as long as the super meter is filled to at least one level of power. Super Moves are activated by inputting slightly more complex motions than special moves. When they are successfully executed, the game will freeze for a brief moment, and then the animation and attack associated with the super move begins. If the super move connects and is not blocked, it will do substantial damage to the opponent. Super moves can be used to turn the tide of a battle. Every player has more than one unique super move.

The number of buttons used during the Super Move indicates the number of levels of super meter to consume (e.g. if the player has two levels of super meter stored, and the move requires the punch button to be pressed, the player may press two punch buttons to perform a level 2 Super Move.) The super meter is then depleted by the level of Super Move performed. A player can not perform a level of Super Move higher than the level of super meter currently stored. Certain super moves require a full 3 levels of super meter to perform, such as Akuma's Shun Goku Satsu, and consequently consume all 3 levels when activated.

Rolling and Countering
Street Fighter Alpha incorporates new ways to evade or counter an attack. One method is the escape roll. To perform an escape roll, you must roll the joystick from backwards to down and press a punch button when you are knocked to the ground by an opponent's attack. This will cause your character to roll forward, changing your position with respect to your opponent so that it's harder for your opponent to combo you. Some attacks will cause you to roll automatically.

Alternatively, if you have at least one level of super meter stored, you can perform a counter attack known as an Alpha Counter. Each character can perform a unique Alpha Counter while blocking an attack. The motion is always back to down, but the button pressed is determined by the character. See that character's move list to determine the proper button. An Alpha Counter consumes one level of super meter, and instantly interrupts the attack that you are blocking. The opponent is sent spinning away from you.

For information on how these rules were changed in Street Fighter Alpha 2, see the section below.

Throwing
The last form of attack available in this game is a throw. Throws are executed by standing immediately next to your opponent, pressing the joystick either towards or away, and pressing a punch or kick button. Some characters are even capable of performing throws in mid-air. If performed correctly, your character will grab the opponent and toss them to the ground in a manner specific to your character's fighting style. Different characters have a different array of throws, so while some characters can throw with the medium or hard kick button, not all characters can. In general, every character can throw with the medium or hard punch button, and no character can throw with the light punch or light kick button. Throws are unblockable.

Taunting
Lastly, your character can taunt the opponent. In the arcade, this is performed by pressing your start button. On consoles, this is typically performed by pressing the select button, or a particular shoulder button. Taunts are generally just for fun, and initiate a short animation for your character. You are entirely vulnerable when this occurs, so it is best to taunt when you feel entirely safe from attack for the next second or two. Some taunts, such as Chun Li's "Gomen nai!" (I'm sorry!) can actually connect and put the opponent in his or her stun animation, while not actually doing any damage to the opponent. In this sense, they can be comboed in.

Rolling and Countering
Street Fighter Alpha 2 changes the aspects of both of these new combat options. In SFA2, when you perform an escape roll by rolling the joystick from backwards to down and pressing a punch button when you are knocked to the ground by an opponent's attack, the punch button used determines the distance traveled forward by the roll. Using the light punch button keeps you stationary. Those attacks which cause you to roll automatically, will make you roll backwards.

Just as in SFA, if you have at least one level of super meter stored, you can perform a counter attack known as an Alpha Counter. Unlike in SFA, every character can now perform an Alpha Counter with the punch and kick buttons so there is no need to know which character uses which button to counter. However, in general, punch buttons are used to counter high attacks and kick buttons are used to counter low attacks. While this is not a hard and fast rule for every character, using the wrong counter can cause your character to whiff and become vulnerable to attack again.

Custom Combos
Finally, SFA2 introduces the Custom Combo. Custom Combos are initiated by pressing any combination of two punch buttons with one kick button, or one punch button with two kick buttons. Any combination will work, and they can be initiated in the air as well. When initiated, your character will increase in speed tremendously, rapidly approach your opponent, and be able to perform multiple moves in rapid succession with no pause between them. You will know that it worked when you see your character followed by a blue trail of shadows.

Custom Combos require that your super meter be at least one and a half levels of power full. When the Custom Combo starts, the meter acts like a timer, draining away and indicating how much longer the character will remain in this state. Any more power beyond one and a half levels simply serves as bonus time. A player can be knocked out of a Custom Combo by getting hit in the middle of it. Making effective use of Custom Combos takes plenty of practice and can produce more devastating effects than a level three super move.

Specific to Street Fighter Alpha 3
In Street Fighter Alpha 3, Capcom introduced 3 fighting systems:

Alpha-ISM (A-ISM), also known in Japan as Zero-ISM (Z-ISM): this ISM is the original game mode of Street Fighter Alpha, you have access to recover during air or ground by pressing or  when falling, air block, Alpha Counter by pressing + when the opponent is attacking your defense (uses 1 Super Combo Gauge and Defense Gauge) and access to all Super Combos of Level 1 (press  or  while executing), Level 2 (press  or  while executing) and Level 3 (press  or  while executing), (Except for Dhalsim, who has an exclusive Super Combo from X-ISM), you can also taunt, but one time per round (except for Dan), this ISM is recommended for beginners.

V-ISM: this ISM is based on Street Fighter Alpha 2, you have access to all things from A-ISM, but you cannot perform Super Combos, instead of this, you can perform the Custom Combo by pressing + while gauge is at 50% to 100%, on this phase, the player attacks will duplicate with a faster combo, but cannot block any attack, exists various types of Custom Combo, this ISM is recommended for professional Street Fighter Alpha 2 players of Custom Combos instead of Super Combos.

X-ISM: this ISM is based on Super Street Fighter II Turbo, your Guard Gauge is bigger than A or V-ISMs, but this ISM is completely different, there is no recovery during air or ground when falling, no air guard, no Alpha Counter, no taunt (but Dan is the only who can taunt on this ISM at any time, the difference is that the down taunt can attack and also be a counter) and one Super Combo Gauge who when full, a Level 3 Super Combo will be executed, this ISM is recommended for professional Super Street Fighter II Turbo players.