From Shoryuken Wiki, Marvel vs. Capcom 3 Strategy and More!

Character States

Both point characters have a continuous character state, used by the game's engine to determine available actions for the characters. Fighting game players often find it useful to group these states into categories, describing characters in one or more states at any given time. The Practice Room's hit box display shows hit boxes in colors, allowing the player to visually distinguish some important character states.

Normal State

Characters have the most available actions during a normal state. These actions include all basic Movement, every attack on their movelist, and the opportunity to Block. Every character has a set of 6 Normal Moves for standing, crouching, and jumping (air) normal states.

Idle animations repeat with small, randomized changes to their timing. If two of the same character can never completely synchronize an idle animation.
Jumping has a throw invulnerable, Xf animation before leaving the ground. Double jumping has a similar period of throw invulnerability.
Most Special Moves can only be preformed once per jump, similar to an air dash or a double jump.
Characters never have additional restrictions on actions when entering normal air state. There are no possible "guard break" tactics after forcing an opponent to recover into an air normal state.
Super jumps restrict calling an Ensemble but are otherwise the same as a normal jump.

Dashing

On the ground, both Dashing and Running do not restrict a character from most other actions. The only exceptions are for dashes. Unlike a forward run, a forward dash will not end early by crouching. All backward dashes restrict blocking until they end. Unlike a ground dash, an Air Dash never allows the character to block until the dash ends.

Attacking

Attack states, including the start up, active, and recovery Frames of every attack in the game, greatly restrict a character's actions. Interrupting an attack state requires a cancel to another move, like a Chain Combo or an air dash cancel. Characters cannot Throw Tech if they are thrown out of an attack state. Getting hit during an attack state, or getting counter hit, does not change the properties of an attack.

Hit Stun

Getting hit puts a character into a hit stun state, restricting nearly all of the actions available from normal state. Hitting an opponent again before a hit stun ends leads to a combo, trapping the defending player with only Ground Recovery and the Infinity Breaker as possible actions. Both of these universal commands require a single button input from the defending player after easily visible hit effects appear around the defending character. Distinct hit stun animations include:

High, mid, and low standing hit stuns
Low and mid crouching hit stuns
Normal, upward, and falling air hit stuns

Knockdown

All characters have functionally identical face down and face up animations. Characters can use Ground Recovery during knockdown, as shown by the colored hit effects that appear below them as they bounce off the ground. Any combo that hits a character after a knockdown uses the one OTG for the combo. Defending characters can use Ground Recovery as soon as they touch the ground if they have already been knocked down once in a combo.

Bounce Stuns

Some attacks cause an extended hit stun, forcing the opponent through either a or effect. The red or blue impact effects seen in a normal knockdown do not appear in these stuns. The defending player can never shorten or soften these stuns with additional inputs, even if they occur more than once in the same combo.

Stagger

The stun leaves the opponent in a unique standing stun animation. All staggers start with a 60f period of vulnerability to everything for the defending player, including throws which would not normally combo. The end of the stagger animation is 20f and is vulnerable to any attack but throws. Players can "shake out" of a stagger and shorten the stun with rapid directional inputs during the stagger. Successfully shaking out of a stagger requires 4 distinct ← or → inputs and reduces the throw vulnerable part of the stagger by up to 15f. After the first stagger in a combo, any additional moves that would cause stagger cause a shorter, normal hit stun instead. If a staggering attack hits against an airborne opponent it will cause a normal hit stun without any additional effect.

Slide

Attacks that cause a stun on hit quickly send the opponent to the ground, causing a . In the first slide stun of a combo, the defending character skids backward along the ground for a set distance before eventually coming to rest then getting up. Ground recovery will not work during a slide stun. If more than one slide stun occurs in the same same combo, or the slide follows a knockdown and OTG in a combo, the defending character can use ground recovery at the very beginning of the slide.

Crumple

On hit, a stun attack causes the opponent to fall to the ground from standing during a unique animation. The stun leaves the defending character vulnerable to any attack, including throws which would not normally combo. The first crumple stun in a combo starts with the defending player standing, causes a , then ends without allowing the defending player to use ground recovery. If more than one crumple occurs in the same same combo, instead of causing a knockdown the stun leaves the defending player completely invulnerable after the initial, standing part of the animation. If a crumple attack hits against an airborne opponent it will cause a normal hit stun without any additional effect.

Ground Recovery

While using Ground Recovery puts a character in a unique state, they are completely invulnerable and unable to take any other action until the animation ends.

Block Stun

Blocking an incoming attack requires the defending character in a normal state. The defending character can use Push Block and Stunt Doubles during block stun to interact with an attacker, meaning a character stuck in block stun is significantly less helpless than one in hit stun. There are 3 distinct animations for block stun: standing, crouching, and air. Distinguishing between a standing and crouching block on the ground requires the defending player to hold the appropriate direction (← or ↙) while blocking. Crouching will block a attack but leaves the defending character vulnerable to attacks, while a standing block defends and gets hit by . Blocking from the air will defend against any attack by holding either direction.

Scripted Animation

Some attacks, most notably Throw and Throw Tech, put both characters into an invulnerable scripted animation. These cannot be interrupted by other characters on screen. Scripted animations will always complete, even if it means holding the timer at the end of the round.

Cinematic

A few Blockbuster attacks cause a distinct, scripted sequence on hit that cannot be interrupted. This includes canceling the move into a Blockbuster Sequel, which means there is absolutely no available action in the game that can stop the animation. What are you going to do about it ragepause?

Skullgirls/Game Systems/States