Catwoman fighting Two-face's (virtual) henchmen inside Panessa Studios.
Freeflow Combat is the smooth and adaptive structure of fighting in the Arkham Series.
General
After starting a fight, reaching a 3 hit combo (Shown in the upper left corner), the character enters Freeflow Combat. As long as the combo is kept, the character can attack further distances, more enemies and gains more speed. However, failing to counter, hitting air or a shielded enemy or not doing anything for longer than 1 second instantly ends the combo.
While the combo counter only increases by 1 hit per attack, each game allows upgrading to Critical Strikes, which increases the combo by two, provided that the player can time their attacks instead of mashing the buttons.
Once the counter turned yellow (at 5 or 8 hits, depending on if certain upgrades were purchased), the player could perform a special move, which served different functions; one could instantly take any normal enemy out, others would temporarily stun nearby opponents, and one could even destroy their weaponry.
Batman: Arkham Asylum
Compared to the later entries in the series, the original game's combat was quite simplistic. Batman could punch, counter, stun and leap over his opponents, and eventually use both the Batclaw and Batarangs as weapons. Ground Takedown, while difficult to perform, awarded the most points if used. Special Combo moves were not initially available, and were upgrades the player could buy.
Batman: Arkham City
The combat system was greatly improved upon, and Batman gained several new moves to use against his opponents. Batman could now use more gadgets in combat, had access to more special moves, and could weaponize the stun move, by using it to initiate a Beatdown or an aerial assault; alternately, he could now knock enemies down (but not out) by swinging his cape at them until they lost balance.
Once he "Freeflow Focus" was purchased, he would begin to experience his surroundings in slow motion once he reached a 12 hit combo without using any special moves. This focus would however be lost if he used any special move during it. An another upgrade, Freeflow Focus Gadgets, allowed him to end the focus mode with the benefit of increasing the power of his quickfire gadgets; this upgrade could not be turned off, however, and only affected Batman.
Batman: Arkham Origins
The combat remained largely the same as in City, but Batman had a different set of quickfire gadgets, and could upgrade his focus to last until he used two special moves. He would later gain access to the Shock Gloves, which, after a brief recharge period, allowed him to punch through enemy defenses for a limited ti
Batman: Arkham Knight
While the system remained mostly the same, several new additions and changes are present. New additions include the ability to strike downed enemies, and picking up downed enemies to finish them up quicker. Additionally, using the aforementioned pickup immediately after knocking out an enemy would cause the character to throw them over their head, adding insult to injury and preventing the player from losing their combo if they didn't notice the knockout. Several changes, however, were present.
The slow motion effect of Freeflow focus was removed. Instead, the characters gain more attack power when it's activated, and it's now tied to the Special Combo meter; It will be activated upon reaching a combo of 5/8 hits. Freeflow focus gadgets could now be used as any character (But not with every gadget; Batman also had to own the same or a similar gadget, such as Explosive Gel and Shuriken/Batarang.)
After Batman gains access to the Batsuit 8.03, the increased mobility of the suit allows him to use his attacker's momentum against them. By timing the counter and holding the movement control somewhere during the counter animation, Batman should throw the attacker to the desired direction. This can knock down any enemies on the path.
The Batswarm move was removed. The same controls now allow certain characters to pick up enemy weapons left on the ground and use them for extra damage and the ability to bypass thug defenses. However, these weapons will break after a few uses.
Additionally, the game introduces Enviromental Takedowns. Certain objects in the surroundings will be highlighted with blue, and getting an enemy close enough allows the character to instantly take them out by using the object.
However, Batman wasn't the only one who learned more moves. Gotham City's thugs also know a few more tricks than before. Even normal thugs could now charge at the character, who in turn could either evade over them or use their primary gadget for a instant knockout. Additionally, they could now grab the character from behind, allowing other enemies to get in a few punches unless they escaped quickly.
In addition, in several parts of the game, players could perform Dual-Play Takedowns, which instantly took out an enemy. They consisted of both playable characters focusing their attacks on a single enemy, and taking them out quickly and effectively. They could only be done in special circumstances where both characters were fighting together, such as when Batman and Nightwing took down Penguin's weapon caches. A wheel in the corner of the screen charged as you hit enemies, and once full, allowed the player to perform the combo. That wheel also appeared on Free Roam if Batman was fighting near the Batmobile, and when full, allowed him perform an Environmental Takedown with the Riot Suppressor Cannon of the Batmobile.