Street Fighter EX2 PLUS/Mechanics

Health

Every character has 200 health points.
All the damage values on this wiki assume that you are at full health and you're NOT playing against Bison, Darun or Zangief. These 3 characters, while they have 200 hp, take less damage in general.
Chip damage can kill in EX2 PLUS.
Normals don't deal chip damage, specials only do so if done outside of EXCEL. Lingering specials, such as Doctrine Dark's explosives, don't deal chip damage, even if they connect after EXCEL runs out. Supers deal chip damage if done raw or cancelled into from a normal, not a special or another super.

Meter

Meter is referred to as gauge in the game, as seen below the "REVERSAL" and "FIRST ATTACK" messages. You can have up to 150 gauge, with 50 gauge allowing for EXCELs, supers and guard breaks.

Spending Meter

Super Cancels

Your go to way to invest meter, as you can cancel into them off of anything, unlike EXCELs.
The slight downside is that they don't build meter like an EXCEL could do, but are easier to utilize offensively.
A jump-in confirm cancelled into super usually deals roughly the same damage as a clean grounded EXCEL hit, if not more.

Meteor Supers (Level 3)

For all of your meter, you get access to a "cinematic" super.
If hit raw, they deal a ton of damage. Some can be cancelled into or used in combos and do more than they would raw (e.g. Pullum jump-in).
Others should be avoided at all costs unless they can win you the game, like Area's Level 3, as she loses her rocket for the rest of the game without a way to recover it.
They all deal roughly the same damage. Some have unique quirks and gimmicks, like different versions depending on range, just frames, followups and mashing, secret inputs and ways of steering direction.
Two extreme cases are Kairi losing 100 of his health and as mentioned previously, Area losing access to her rocket and every punch move for the entire rest of the game.

Guard Breaks

Guard breaks can be done by inputing a punch and a kick of the same strength (LP+LK, MP+MK or HP+HK). Almost all guard breaks have a large ammount of startup and can be reacted to.
Not all of them are equal, while some even have special properties, like being airborne, letting them dodging most low hitting moves. They can also have deceptive ranges due to forward advancing movement or hitsphere extensions.
As the name suggests, guard breaks are unblockables. When you're hit by a guard break, you're put into a stun state which can be mashed out of. Doing so will let you avoid jump in starters.
After wakeup, there is an extended period of invulnerability to guard breaks and hitting two of them too soon after one another will cause a knockdown, even though the opponent might have recovered already.

Nanase's Guard Break

This is the only guard break in the game that can be charged by holding down the buttons, extending the range of her staff to almost halfscreen length.

Cancel Breaks

Basically the same as guard breaks, but cancelled into from blocked/hit specials and supers. Even moves with invulnerability on startup, like Ryu's Shoryuken, can be cancelled, as long as you input the cancel break while grounded after it connects with the opponent.
Hitting your opponent with a cancel break after a special or super move hits them will cause them to get knocked down instead of being put into a stun state. This usually even combos, but if hitconfirming your special or super, there is no reason cancel break.
Some characters, like Sagat, can utilize cancel breaks as combo tools.
Inputting a cancel break will trigger a "CANCEL BREAK" message under your health bar to indicate the difference, as raw guard breaks have no message of their own. Essentially they are the same, but the hitstun inflicted by a cancel break is way lower.

Pullum's guard break = +31 to +92 (toolassisted mashing vs no mashing)

Pullum's cancel break = +16 to +51

What a cancel break also does is remove any active move that is being blocked and while immediately ending blockstun. This denies any sort of "unblockable" setups one could think of.

EXCEL / Extra Cancel

One of the defining features of this game, which is why it has its own page over at EXCEL

Gaining Meter

First Attack

Hitting the first attack of a round builds you 25 additional meter. Trades will give 25 meter to both players. A successful throw, super or guard break as first hit will also trigger this effect.
Round start guard breaks, as gimmicky as they are, can allow for optimal combo starts for a majority of the cast.
If the first hit of a round is done during EXCEL, the first attack message will trigger, but build no meter.
Most characters get to build 50 meter if they get the first attack from a jump-in combo.

Reversal

Getting a proper reversal input on a special or super move allows you to build 15 meter.
The reversal window is at 2 frames, so the timing for successful reversals is rather tight. This can be triggered on wakeup, after air resets and hitstun/blockstun.

Self Knockdown

Some moves in the game cause the player that used them to get knocked down as well.
This applies to Kairi's P throw for example.
Most of them are easily recognizable, as your character gets up of the ground like they would after a knockdown. This special case of knockdown also allows for reversals.

Tech Hit (throw tech)

A "TECH HIT" is what the game calls successful throw techs. It gives both players 15 meter.
Obvious throw attempts can be used to build meter if the opponent can reliably throw tech. This can also be used to deny building meter, as landing a throw gives noticeably less.
Keep in mind that the window for teching throws is only 4f after the throw initiated.

Whiffed Specials

Great to use when having a knockdown with large frame advantage or right as a screen shift is about to occur. Moves with airborne followups, namely the rekka sequences of Ryu and Kairi, can be continued offscreen to keep building meter.

Attacking / Blocking

Any move that connects, whether on hit or block will build meter.
Any blocked hit builds 1 point of meter for the defender. For the attacking player, light normals build 1 point of meter, mediums 2 points and heavy normals builds 4 points. The numbers for blocked specials vary.
The same goes for any move on hit.

Throws

EX2 PLUS has single button throws, just like Super Street Fighter II Turbo.
Throws have no startup, if two players input it at the same time, the throw will still be teched.
You only have 4 frames to tech after the throw input. There is no tech option if you are being thrown during a moves animation, whether its on startup or recovery.
After teching a throw, there is no frame advantage for either player.
Most characters have their throws on medium and heavy normals. Some are missing a punch or kick variant and others can only use their heavy normal to initiate it.

Option Selects

Priority OS

Since LP>LK>MP>MK>HP>HK applies to input priority, using LP+MP/HP or LK+MK/HK as throw inputs is usually ideal, unless the medium/heavy normals do something you would like to come out instead.
If the opponent is able to be thrown, you just get the throw, if not, a light normal comes out instead of a medium or heavy one.

Crouch Tech OS

To initiate a throw, only 4/6 are allowed as directions.
This does not apply to the defender, as they get to hold any direction that is not 2/5/8, so inputting 1LKMK can function as throw tech. If the timing is correct, you tech if they go for a throw, block if they frame trap or mash out if the gap is big enough. This will get beaten if those options are delayed.

Throw/EXCEL OS

Every normal in the game can be cancelled into EXCEL if the second button is input 1 frame after the first.
In combination with throws having no startup, this allows for EXCEL/throw option selects. If the opponent cannot be thrown, the normal will be kara cancelled into an EXCEL activation.

Kara Cancels

Specials

7f window after inputting a normal for every normal, including jumping normals and command normals.

Supers

18f on whiff to cancel any normal into a super.

Guard Breaks

1f only to cancel a normal into guard break.

EXCEL

1f only to cancel a normal into EXCEL.
"Plinking" anything with the proper button combination will result in a kara EXCEL activation.
Very important for Vulcano Rosso's grounded EXCEL loops, as his 5MP moves him forward by a lot on its first frame.
Any normal can be kara cancelled, so certain air "normals", like for example Dhalsim's j2K can be kara cancelled to stop air momentum, same with Area's j2HP.
A very unique case is Garuda's 6HK as it is the only normal move that is airborne on frame 1. This allows him to kara EXCEL from the ground and end up in the air, similiar to what a short hop would look like.

Juggle States

Most normal hits against an airborne opponent put them into an air reset juggle state. After the initial frame of hitting, there are roughly 28 frames of the air reset animation. This is the same for any kind of normal used, but a followup can only be achieved depending on the recovery of the move, usually by jumping forward with an air normal, or if a special can reach them, by cancelling into it.
This air reset juggle state will restand the opponent upon landing and allow them block or reversal to build meter.
A similar juggle state is one with moves that have knockdown properties, such as most specials. In this case, instead of air resetting onto the ground standing, they will just get knocked down. The juggle properties afterwards remain the same.
One unique juggle state is that of Vulcano Rosso's 236P->6P move, which keeps its juggle property until the opponent touches the ground.
A juggle off a regular hit is not actually possible due to height and recovery, unless cancelled into the last followup with 6K. This followup is probably the reason why it has that juggle state in the first place.
With proper height on the 6P followup, the juggle can be turned into an infinite, as 2LK will now hit the opponent before the knockdown and allow for continuous 236HP->6P juggles

Screen Shifts

45-46f knockdown advantage after, might vary for certain moves.
Special moves that are interrupted by screen shifts still build meter.
As mentioned under Whiffed Specials, Ryu and Kairi get to keep going with their airborne rekka sequence, delaying the screen shift until they are no longer airbone.