Because combo breaking is such a unique concept to Killer Instinct, it can be a little difficult to apply existing skills from other fighting games. So let’s take a page to discuss some of the strategy required, both offensively and defensively, to use combo breakers to their full potential. This page is a little less flashy than others in this tutorial, but it's useful stuff, so stick with me.
The Right Philosophy
Unlike other fighting games, landing a hit in Killer Instinct does not reward you with your biggest combo until the defender makes a further mistake, which means winning the footsies war, landing a post-knockdown hit, or baiting a reversal is only step one towards punishing your opponent. While this can initially be frustrating, first hits are awarded often in KI, and fully invincible reversals rarely lead to big damage, which means offense is strong and breaking the combo is the real risk for a defensive player to take. Plus, you can do pretty reasonable damage before completing your opener, which is all unbreakable, making sure that even if the defender breaks immediately, you will still get rewarded.
It’s best to treat combos in KI like any one-sided battle in a fighting game, such as pressuring a knocked down opponent. The offense has full control over the situation and the defense must take a risk to escape. The difference in KI is that the best case scenario for the defense is simply avoiding further damage and a return to neutral, but the best case for the offense can be more than half of a life bar. Just like how your reward for landing a sweep is knockdown pressure in most fighting games, landing an opener in KI can be thought of as obtaining combo pressure, and you do continual damage to your opponent while he weighs his breaking options.
Combo breaking in KI is hard; doing it on reaction or anticipation is a skill that requires a lot of practice and game knowledge. Choosing to guess break the strength of an attack is definitely possible, but it’s a guess that heavily favors the offense. Not only are the 1 in 3 odds of success weighted against the would-be breaker, but the offense can choose to take a big risk and play his counter breaker trump card at will to make all defensive guesses incorrect. Guess breaking is a strategy that has its place (and sometimes you need to guess, because the offense can choose to use only unreactable moves in his combo), but you shouldn't immediately guess every time you get hit. Guessing can never replace skilled defense backed by solid game understanding, and cannot lead to long-term success alone.
Defensive Strategy (a.k.a. When and What to Break)
One of the more difficult things in Killer Instinct is the need to constantly switch between traditional offensive footsies and defensive combo breaking. Unlike other fighting games where you’re able to take a quick mental break after you lose the neutral game and start getting comboed, in KI you need to immediately begin trying to identify your opponent’s combo and think about combo breaking. This repeated back and forth is quite mentally taxing and requires a lot of concentration, which is partly why KI is so exciting to play. Until you get locked out, there’s always something to think about and react to.
The first thing to decide is when to break. Trying to break very early after the opener is risky, because if you get locked out, your opponent will have lots of KV meter to use for his damage loop, and the combo will likely hurt a lot. On the plus side, breaking early means you take the least amount of damage possible and will likely frustrate the offense, who is unable to get anything going. If you choose to break late, the offense is unlikely to have hit you with his highest damaging combo (since he is probably avoiding too many easy-to-break heavy attacks), and the penalty for being locked out is considerably less, since your opponent has spent all his KV meter already. However, the offense might be more willing to counter break, considering he has done a fair bit of damage in the rest of his combo, and sometimes he'll just finish his combo with an ender earlier than you'd hoped, leaving you to just eat all that damage while you were waiting. I would advise you mix up your break timing; sometimes break early and other times break late, even if you have to guess on occasion. Evaluate the state of the game and the emotional temperature of your opponent to better judge these risks.
You also have to decide what to break. Most of the time, this will mean choosing between the auto-double/manual, or the linker. Most beginner players will try to break only auto-doubles, because heavy doubles are easier to react to and they’re expecting one to eventually come, but this means the offense is free to use heavy linkers and open up all their manual options. You may find some characters' linkers to be easier to identify than their auto-doubles, and if you’re playing against someone who uses manuals a lot, you might try to break the linker more often. Try to get a sense for patterns in the offense, particularly against beginner players who will frequently use the same strength linker after certain auto-doubles due to muscle memory.
I can also offer some preliminary advice on how to break. Ultimately it would be nice if you could react to every move, but reacting to the correct strength of manuals and light auto-doubles is virtually impossible to do reliably. It helps to take a look in training mode at the animations for the auto-doubles of any character you're struggling to break, but remember that auto-doubles will feel pretty similar between characters, so learning audio cues and visual pace for the hits can help. If your opponent manuals repeatedly and you don't want to guess break, you can try breaking the linker. Some linkers offer different startup sounds and slightly slower or faster first hits depending on the strength of linker used, which can be a big help if you want to dig into this deeply, and linkers where the offense executes multiple versions of the special move are much easier to break on reaction than others. Lastly, it can help to look at your own character as you're getting hit. Being hit by a heavy attack will always cause your character to reel a certain way, and it's different for mediums and lights. This means you just need to learn to look at your own character's animation, rather than try to learn the animations for all your opponent's moves. But in reality, some combination of all these factors, plus figuring out opposing player's habits, is what will help you become a consistent combo breaker.
And finally, sometimes it’s okay to not break. Not only might your opponent try a poorly-timed counter breaker and give you a free opening, but unless your opponent is going all heavy attacks all the time, you can afford to take a few full combos to learn some information on your opponent’s capabilities. Does he use manuals? How often does he use heavy auto-doubles (can you wait for one, or do you need to give up and break something else)? After the opener, is he always pressing the same button? You can use this information to your advantage later in the fight, when a clutch combo break is most important.
Offensive Strategy (a.k.a. How to Avoid Getting Broken)
While it can be annoying to get combo broken often, it helps to remind yourself that the system favors the offensive player. Breaking is hard and the reward is minimal for the defender, so even one successful lockout can make up for several combo breaks. If your opponent is repeatedly combo breaking the same point in your combo, the answer is simply to counter break them and hit them for 60% life or more. If you can do this even twice in one match, you’ve effectively won it, which makes it a risk worth taking if your opponent insists on repeatedly combo breaking at predictable moments.
If you’d rather not take the risk immediately, the best strategy is to fish for lockouts. If you notice your opponent constantly breaking lights, just change the strength of your attack and earn a lockout. This is much less risky than a counter breaker, and can still earn you good damage in a combo. You can also throw in some manuals to throw off your opponent’s break timing, in addition to making the strength of your attack difficult to react to.
The idea is to vary the strength of your attacks considerably at the start of the combo. Use all strengths of doubles, manuals, and linkers as interchangeably as you can. You might spend some KV on some light auto-doubles, or lose damage by avoiding heavy attacks, but you’ll earn many more lockouts. Once you earn a lockout, switch to heavy auto-doubles, but keep an eye on your KV, as it’s already likely pretty high. You can also choose to spend meter on shadow linkers when your opponent is locked out to quickly raise the ender level for maximum reward; this strategy works even when your KV is high and is a great use of shadow meter.
You can also set up some really interesting resets. Because throws and light combo breakers are mapped to the same buttons, sometimes it pays to set up a situation where your opponent might try to break lights (for example, perform a light linker, setting up the possibility of a light manual), and then simply just neutral jump. If they try to break, they’ll actually get a high recovery throw instead, allowing you to reset with a fresh KV meter. You can do similar things with medium breaks, where you drop the combo and then hit them with a delayed attack to counter hit the medium punch that will come out. If you’re able to successfully reset them, consider doing a one-chance break combo. This is a combo that gives them the minimum number of chances to break before you perform an ender; after your opener, do exactly one auto-double, linker, or manual, and then end the combo (remember, going from opener directly to ender is breakable). If you choose to do a light auto-double or light linker, it may happen so fast that your opponent does not even realize what has happened before you end the combo and cash out a large amount of white damage. Resets mixed in with the already difficult-to-defend variation of linker, double, and manual strengths increase the power of the offensive game considerably, and will force the defense to start guessing.
As a more general idea, think about the combo as a footsies war where you have total control. Feel free to test your opponent’s reactions and habits in the first few combos and accept some breaks for the purpose of gaining information. Will he react to my heavy auto-doubles, or am I free to use them for damage? Does he mash on a random breaker strength as soon as he sees his character start to get hit? This is very similar to how good players will approach knockdown situations in Street Fighter games; they will run very basic offense on you (such as basic tick throws, or a standard frame trap) until you’ve proven you can stop it, and then they will break out the next-level reads and tricks. In KI, don’t go for a counter breaker until your opponent has proven he’s capable of breaking multiple times successfully. There’s no point in assuming that risk when your opponent is willing to lock himself out. If your opponent can’t handle small variations in your combo, play basic offense and take your free win.
The final trick in the bag is to take the information you gained on their breaking habits and use it against them. If you know they like to wait for heavy auto-doubles to break, you could simply choose to avoid heavy doubles in your combo. But, for extra big damage, you could use a heavy auto-double at an opportune time and then counter break it. Not only will you get big damage in the short term, but a smart player will be reluctant to break reactable moves in the future, giving you more leeway in your combos. This is what makes KI so satisfying to play. If you know what your opponent is going to do, you can take an action that will heavily reward you for it.