The Basics
Throws
Throws in Killer Instinct are performed by pressing LP + LK when near an opponent. They are unblockable but short-range attacks that complement attacking and blocking in the rock-paper-scissors exchanges of fighting games. You can leave the stick in neutral or hold it forward while pressing the buttons to throw forwards, or pull the stick backwards to perform a back throw that switches sides with your opponent. You cannot throw someone who is in blockstun.
Throws can be defended against by pressing LP + LK when your opponent tries to throw you; this is called a throw tech. When achieved, both fighters will break away from each other into a neutral position. Killer Instinct gives you 7 frames after the throw connects to tech, and throws have 5 frames of startup, equal to the fastest normal attack. Throws are great for fast, close-range mixups that will force defenders to take action other than blocking to escape your pressure. They play a pretty similar role to Street Fighter throws, but Killer Instinct throws have a couple very noteworthy properties.
Perhaps the most important distinction is that there is no crouch teching in Killer Instinct. In fact, if you attempt to crouch tech, you will simply perform a standing throw. Street Fighter V throws behave the same way, but if you played a game like Street Fighter IV and built up the muscle memory of plinking LP and LK together to prevent throws, both on offense and defense, that is a habit you will have to quickly break. It additionally means that defending against throws is hard in KI, because there are very few risk-free ways to avoid your opponent's throw. If you decide that teching a throw is too risky, your only other options are to interrupt a throw attempt with a normal, or avoid it by jumping or performing a throw invincible move; each of these options carries a large risk. Because you cannot remain crouching while trying to tech, walking slightly out of range and performing a low move is a strong strategy in KI.
The second noteworthy change is that throws have very long whiff recovery in Killer Instinct. In modern Street Fighter games, baiting throws with neutral jumps is a recipe for getting anti-aired, since the throw whiff will recover before most characters can connect with a jumping attack. However, neutral jumping or backdashing to bait a throw in KI is an excellent idea that will often earn you a very large punish. In fact, neutral jumping is one of the primary ways to bait throws for Killer Instinct players, so expect to see it a lot. If you are able to recognize these situations and avoid the panic throw whiff, you can anti-air the neutral jump and start to go on offense yourself.
In Killer Instinct, some characters can start a combo off a successful throw. For instance, Jago and Sadira can start air juggles off their throws, while Thunder, Glacius and others can start grounded combos. For more detailed strategies involving these throw combo starters, check the Characters page.
In most fighting games, just like block stun, it is also impossible to throw someone in hitstun. In Killer Instinct, this is true in almost all cases as well, although there are two specific cases where you are allowed to throw someone who is in hit stun: after a wall splat ender or after hitting with a move that staggers. If these two conditions are not met, or your character's combo trait does not specifically break some universal game rule (like Thunder's throw linkers), then you cannot throw someone in hit stun.
Lastly, let’s briefly mention other types of throws. Orchid has an air-to-air throw executed with LP+LK, which cannot be teched by any character, including Orchid herself. This throw also leads to a full grounded combo. Some characters, such as Thunder, TJ Combo, Kan-Ra and Hisako, have command grabs; these are powerful special moves that function as throws and cannot be teched like traditional throws. The only way to avoid a command grab is to move out of the way, typically by jumping, trying to walk out of range, or by doing a move that is throw invincible. Finally, Maya has an air command normal called Air Mantis ( + HP) which will lunge at opponents from the air and connect with any standing or jumping opponent, but never with crouching opponents.
Knockdown
You can knock your opponent down in Killer Instinct with a variety of attacks, including certain normals like sweeps, throws, and combo enders. While you are knocked down, you cannot perform any actions and you cannot be hit except by a few very rare OTG moves. In Killer Instinct, there are two types of knockdown.
Hard knockdown forces your opponent to lay on the ground for a predetermined amount of time (in the ballpark of around 60 frames). It is the strongest type of knockdown possible, since it allows the offense to pressure the opponent when they rise from the knockdown with techniques that require some setup time, like a jumping crossup. All throws and sweeps cause a hard knockdown, as well as some specially marked combo enders. If you get hit by these moves, watch out, because some scary offense is coming your way.
Soft knockdown gives your opponent a chance to quick rise when they first hit the ground. You perform a quick rise by pressing any attack button the moment your back hits the ground. Your character will then immediately rise off the ground without having to suffer the hard knockdown delay, which will often make sure your opponent doesn’t have enough time to set up his strongest offense. If you choose not to quick rise, you will suffer the normal hard knockdown delay and then rise automatically. Most knockdowns in the game are soft knockdowns. This includes virtually all special moves that knock down (for example, Jago’s Tiger Fury uppercut), any time you are juggled in the air, and most combo enders.
When you rise from a knockdown, there is a moment in time when your character becomes vulnerable to attacks again. In Street Fighter games, this moment in time varies in value. Many characters in Street Fighter IV, for instance, thrive on knocking you down and earning large chunks of damage with very difficult to block mixups, while wake-up pressure is not nearly as strong in a game like Street Fighter V. However, knockdown pressure is very scary in Killer Instinct. In order to escape this pressure, you might try to use an invincible reversal attack, if your character is lucky enough to have one. In general, it is difficult to make these invincible reversals safe if they are blocked (Street Fighter IV has a mechanic called FADC which made safe-on-block reversals very common, but invincible moves are always unsafe in Street Fighter V). In KI, they are almost always win-or-lose gambles.
But even though reversals are risky, you will be forced to try them on occasion, because some knockdown mixups are closer in spirit to the high-octane Marvel vs. Capcom series of games than the typically more reserved Street Fighter series due to the strong offensive options of the Killer Instinct cast. More details can be found in the Characters section, but the two videos below give a small preview of what you might expect after a knockdown against some of KI's more potent rushdown characters.
Due to the nature of KI’s combo system, reversals that send an opponent airborne very rarely lead to large damage, whereas your punishment if your reversal does not hit can be extremely high. This means gambling on reversals often is not in your favor long term and you will have to pick and choose your spots very carefully.
If you choose to do a reversal special move, it is not difficult; Killer Instinct has an input buffer in place that allows reversals to be executed slightly early to ensure they come out on the first frame possible. This means you should try to time your reversal slightly early in order to take advantage of this. This buffer window is made even larger when rising from the ground, making wakeup reversals easier than reversals out of blockstun. If you perform a special move as a reversal, Killer Instinct displays a "Reversal" message to let you know your timing was correct.
Because Killer Instinct’s jumping system works very similarly to canonical Street Fighter games, safe jumps are possible. Most invincible reversal attacks can be safe jumped, except those rare uppercuts that have only 3 frames of startup (only Jago, Orchid, Fulgore, Shadow Jago, and ARIA have such moves); these attacks start too fast and will hit your safe jump before you can land and block. However, since hard knockdowns are less common than soft knockdowns in Killer Instinct, and post-throw offense tends to prefer very strong crossup or high-low mixups, having encyclopedic knowledge of safe jump setups is not at all required to run strong offense after a knockdown.