Basic Mechanics Overview
Older video that's a little more comprehensive about basic mechanics:
As with most games covered on this wiki, Chaos Code uses numeric notation. If you aren't sure what means what, look at the number pad on your keyboard.
For instance, 5 is neutral, 2 is crouching, and 236 is a quarter circle forward ("hadouken") motion.
Run/Step - 66
Depending on your selected bounce, pressing forward twice will move your character forward with either a Step or a Run. A Step is a relatively short Dash that cannot be canceled from but can be canceled into. Some characters stay on the ground when they Step, while others have a short hop. There is some lower body invincibility and throw invincibility on hop type steps due to them being airborne. A run allows you to hold forward and continue moving the character and can be canceled at any time (though there is some recovery when trying to block). Runs allow for more control over mobility and open up using "micro-dashes" aka runs immediately canceled into normals which can extend the range of moves and open up new combo routes. Celia and Cthylla have unique dash types, for them Run moves them off the ground diagonally forward and Step cannot be canceled into, but can be canceled from similar to other character's runs.
Backdash - 44
Regardless of your selected bounce, pressing back twice will move your character backwards. Backlashes have a few frames of invulnerability on startup.
Every character can build up to 3 levels of super meter, each level being further broken down into 2 halves. The look of the super meter will depend on your selected bounce. When using Run the two halves of the meter are slightly offset, and when using Step the two halves are more distinctly separated parts. The difference is mostly cosmetic, however the Step meter is slightly shorter, which means meter will be built faster for characters using Step.
Jump - 7, 8, or 9
Pressing up or diagonally upwards makes the character jump. Character jump speed and distance are not standard. There are 2 frames of Pre-jump, during which you cannot block low but can block high, so if you want to punish someone's jump-out attempt you'll need to low them.
High Jump - 1, 2 or 3 then 7, 8 or 9
A higher than normal jump. Also known as a "Super Jump"
Double Jump - 7, 8 or 9 after a normal jump
Pressing up or diagonally upwards again while already in the air propels your character again in a double jump. The first frame of a double jump is vulnerable, so it is not possible to up-back and block/double jump out of air reset meaties
Air Dash - 44 or 66 in the air
While in the air, press forward or backward twice to air dash in that direction. You cannot air dash after a double jump and cannot double jump after an air dash, you can however air dash after a super jump. By inputting 96 or 74 you can buffer an air dash input to happen as soon as you hit minimum air dash height, this is commonly known as an "Instant Air Dash" or "IAD"
Air Dash Break
An air dash can be canceled at any point into an attack, doing so will stop the air dash animation early causing you to drop quickly. This lets you do very quick overheads from an IAD and then land immediately, creating a jump arc more similar to a "hop" from an SNK game than a traditional air dash.
Chaos Code will buffer held inputs indefinitely, meaning if you hold down the A button you will get your light punch at the first possible frame you can act. This only applies to single input actions, so anything more complicated than 1 direction and any number of buttons will not work and instead that input must be done within the game's general input buffer (which is also fairly large, tho not infinite). Any changes in directional input will clear the infinite buffer, so if you want to buffer something like a 2A make sure you input the direction first, and then the button.
A+B - Roll
Both weak buttons will cause your character to slide forward for a bit. If you've ever played any of the numerous SNK fighters with rolls, they function pretty much the same way here. You are temporarily invincible to all but throws while rolling, but can be punished on recovery if you aren't careful.
A+B when recovering - Tech
When an attack's hitstun is over, you can press A+B to recover. If you do not recover you will stay in hitstun until you eventually recover automatically. If you want to tech as soon as possible you can hold down A and B and the tech will be buffered, but keep in mind that any directional inputs will clear this buffer, meaning if you want to buffer a directional tech you should first hold the direction, then hold the buttons.
A+B when recovering in the air - Air Tech
If you recover while in the air by pressing A+B you will "Air Tech". This can be done neutral, forwards, or backwards. Each direction gives you different momentum, alternate between them to keep your opponent guessing where you'll end up. You can air tech at any point after hitstun is over & before you hit the ground. If you don't hit the ground you'll enter a soft knockdown.
A+B when recovering while on the ground - Ground Tech
On the ground after a soft knockdown you can press A+B to get up faster with a roll animation. This is called a "ground tech" or "tech roll". There is only 1 timing for ground tech. After a ground tech, there is 1 frame where you cannot perform any action except block. If you try to do anything the game will put you in neutral for that 1 frame before taking whatever action you input, meaning you cannot reversal.
If you are hit after an air tech would have been possible, that hit will still be scaled as normal and the combo counter will increase, but will turn purple to indicate a tech was possible. This is called a "black beat", "blue beat" or "purple beat".
A+C - Throw
By pressing both punch buttons, you can perform a throw on your opponent. Throws cannot be blocked and instead must be teched by inputting your own throw just after being grabbed. Normal throws have a universal startup of 5 frames. Additionally, throws have 1 frame of invulnerability on active, which means both that they usually win trades and that if both players input throw on the same frame they'll whiff through each other rather than tech.
Throw Break OS
Universally, A+C+D will give a throw break if you are thrown or a Tactical Guard if you are in neutral provided you have enough meter. This is a very common defensive OS. For some characters, A+B+C will give roll when in neutral giving them an alternative OS. Characters who can use the Roll/Throw break OS are Kagari, Cthylla, Bravo, Rui, Ray, and Lupinus. For Kudlak-Sin and Celia II Kai A+B+C will give Exceed in neutral when at 3 bars, this is not commonly used as an OS but it is possible.
6+C+D - Guard break
At the cost of a single bar of meter, you can instantly crush your opponent's guard. This is unblockable and does a lot of stun damage. If you blockstring into it the damage and stun of the guard crush will be reduced.
C+D - Tactical Guard
If you see an opponent's attack coming, press both kicks to repel it and get a free counter hit. Can also be done in the air. This does not work on projectiles and combos starting off a tactical guard are heavily scaled.
A+B or 6+A+B - Chaos Shift
A way to cancel the animation of your super for 1 bar, similar to RC mechanics from ASW games. Holding forward will cause you to auto run. A good mechanic for combo extension or to protect yourself if something goes wrong. Not all supers can be Chaos Shifted, which ones are shiftable when is dependent on the super, some can be chaos shifted even on whiff and some can only be shifted on hit. Additionally, Catherine's EX devil stomp has a bug that allows it to be chaos shifted
By pressing attacks in a specific order (A>B>C>D) you can chain them together on hit or block both on the ground and in the air. This only applies to cancelable attacks, so check your character's movelist section to see what can be canceled and what can't. From any cancelable normal attack, you can then cancel into a command normal provided your character has one, and then into a special or super move if the command normal used is cancelable. For example, a chain sequence that Rui can do using this system is: 5A > 5B > 2C > 6A > 214A.
High Jump Cancel
Any cancelable normal or command normal can also be canceled into a high jump. This is typically called a "super jump cancel" or "sjc"
Special moves can be canceled into super moves for the cost of 1 additional super meter (so 2 total), this also unscales the damage of the super, making it more damaging.
Super moves, or Ultimate Chaos attacks as the game calls them, are performed at the cost of a single bar of meter. You can cancel into supers from any cancelable normal move at the cost of 1 bar of meter, and from most special or EX special moves for 2 bars of meter. In exchange for the extra bar, damage scaling on supers canceled from specials gets reset.
At the cost of 3 bars of meter, each character can perform a very powerful super move. The properties and damage of each move depend on the character.
When selecting your character, you are presented with four attacks: two special and two Ultimate Chaos attacks. You can choose any 2 of those attacks to take with you for the match. Extra moves are often some of a character's strongest tools, so choosing which ones you want for a matchup is very important.
B+C - Exceed Chaos
At the cost of three stocks of super, you can perform an invincible "burst" that pushes opponents away and enter an enhanced mode that allows access to combos that are not normally possible. Despite looking like an ASW burst, you cannot use this to escape combos instead, you get to use super meter infinitely (but you cannot use Destruction Chaos), and will gain health passively. But, when the time runs out you will lose access to your meter until the overheat timer ends. Exceed Chaos can be cancelled into from any cancelable normal, or any special move.
Beneath the character's life bar is a purple meter that fills while the character is being attacked or comboed. When it fills, the character is knocked down and recovers in a dizzy state. Dizzy will slowly decay as you avoid being hit or blocking attacks.
Each additional hit within a combo will deal less damage than the hit before, this will continue until a combo has gone on long enough that moves are dealing their minimum damage (usually ~100). If a combo lasts past 40 hits then the minimum damage on moves will be removed, and they'll start doing a minimum of ~10 damage per hit. This harder scaling on long combos doesn't apply to stun.
If an opponent is put in an OTG state, the cap on damage scaling will be changed from 100% to 70%. This also happens after most moves that wall or ground bounce as well as many that launch. This scaling works the same as scaling penalty in exceed combos.
Absolute Guard Break
If a move connects on or just after the frame where blockstun ends absolute guard and buffered inputs behave strangely. If it's timed perfectly the opponent will not leave blockstun and cannot act, but also will not have absolute guard and must continue to manually block. If it's timed one frame later the opponent can only reversal if they are not holding back.
Unlocked in collection is "chaos mode" which gives characters all of their extra moves in exchange for a 20% damage decrease on all of their attacks. Chaos mode will also prevent you from choosing run or step, instead you'll get a new super meter which gives step's meter gain and dashing will cause a run for all characters except MG Hikaru, Bravo, Ray, and Rui who will have their steps instead.
Unlockable for every character, Boss mode gives characters new tools and properties as well as all of their extra moves. The properties of each boss character are different but in general they are supped up versions not intended for competitive play. Notably, Celia II Kai and Kudlak-Sin's boss mode changes them into Celia II and Kudlak, the versions of them that are fought in arcade mode as the actual bosses of the game and who were playable in the previous PS3 release.