The Basics
What is Killer Instinct?
Killer Instinct is a 2D fighting game published by Microsoft Studios, available with cross-play and cross-buy on Xbox One and Windows 10 PC, and also on Steam. The game is directly connected to Killer Instinct and Killer Instinct 2, fighting games developed by Rare in the mid-90s which were released for arcades, Super Nintendo, and Nintendo 64.
The current version of Killer Instinct was released as an Xbox One launch title in November 2013, developed by Double Helix Games. It launched with six unique characters and expanded to eight by the end of Season 1. In September 2014, Season 2 launched with new developers Iron Galaxy Studios, who eventually expanded the roster to eighteen characters over the course of 2015. Season 3 launched in March 2016 and completed development at the end of the year, adding eight new fighters for a total of twenty-six. Killer Instinct then released three new standalone characters (Kilgore, Shin Hisako, and Eagle) in the first half of 2017, which exist outside of the seasonal structure the game was built on.
There are 29 characters in Killer Instinct, each of them a unique mix of traditional fighting game archetypes and new ideas. Check out the Characters page for more details.
You can buy Killer Instinct on the Microsoft Store (for Windows 10 PC and Xbox users), or on Steam. The MS Store offers a free to play version, so you can play online with a limited roster to your heart's content without paying a cent. Then, you can upgrade to the Definitive Edition, which often goes on sale for $10, if the game hooks you. Both versions offer all the content, and can even cross-play with each other in some modes. If you want to know which version you should buy, or the similarities and differences between them, check this page for a full breakdown.
Health & Damage
Your goal in Killer Instinct is the same as any fighting game; do damage to your opponent until their health bar is fully drained. In KI, this means working your way through two different life bars, the first green and the second red. When a health bar is drained, it disappears from the screen until the current combo is completed, and then the next round starts after a brief pause. The camera and character positions are not reset, and the players are free to move around (but not attack) while the announcer says "Ready"; if you were KOed in the corner, this might be a good chance to reposition yourself. The player who performed the KO does not get any health back and must fight on with their current life bar.
When you drain your opponent's second life bar to 15% remaining, he will enter danger state, which indicates he can be hit by an ultra combo. When a character's second life bar is fully drained, the match is over. If time runs out, the character with the most remaining health wins the game. All characters have the same amount of health in Killer Instinct, and there is no stun or dizzy state in the game. (Note: ARIA has the same total health as other characters, but it is split across three health bars.)
When a move is performed in neutral, or as the first hit in a combo, it does twice as much damage than if used in the middle of a combo. This means stray hits and anti-airs do lots of damage and players should start punishes with strong-hitting moves wherever possible. Counter-hits also do extra damage, around 25% more. Hits performed in the middle of a combo will do a portion of their damage as white (or potential) damage, which will linger on a player's health bar and slowly start to recover 3 seconds after they last took damage. For more details on how to cash out this white damage, see the Combos section. Killer Instinct also employs damage scaling in the middle of combos.
Movement
Movement in Killer Instinct is very similar to a traditional 2D fighting game. Every character can walk forwards and backwards; the speed at which they do this is character-specific and strongly influences their footsies game. Walk speeds in Killer Instinct can be vastly different. For example, Orchid and Shadow Jago walk very fast, while characters like Hisako and Glacius walk very slowly and often prefer to use other tools to move around the screen.
Every character can jump, and you cannot block while jumping, making each jump a large commitment. Most characters have strong anti-airs that do good single-hit, unbreakable damage, and some may lead to more combos depending on resources spent. Against the characters with strong anti-airs, you can expect to take 15-17% damage for a poor jump, or as high as 30-35% if the opponent spends multiple resources and gives you a chance to combo break.
Not all jumps are the same. For example, Jago's jump takes around 4/5ths of a second from start to finish. This is pretty comparable to the average jump time in modern Street Fighter games. Some characters with extra strong ground games, like Thunder and Glacius, have "floaty" jumps that take quite a bit longer to complete. When you land after performing any jumping attack, you are vulnerable for a short time by something called trip guard.
While you can never block in the air, some characters can change the angle of their jump to try and avoid being anti-aired. Sadira, for example, can double jump in the air or zip towards the wall with a special move. Maya can jump while rolling on the ground, which makes her jump farther than normal. Omen and Cinder can choose to dash in the air, either by inputting a standard dash or a unique special move. Roughly half the characters in the game have a way to control themselves in the air to some degree, but jumping is still risky for these characters.
Every character can quickly move forwards and backwards by tapping a direction twice; most of the time, this results in a dash. Like walking, each character's dash has a unique distance and speed, which means not all dashes are made equal and some characters will prefer to dash more often. Jago's dash can be considered "average" in many ways, as it compares favorably to standard dashes in Street Fighter games. Some characters have much slower dashes that are large commitments (like Aganos), while other characters have incredibly fast dashes that can be used as a primary means for moving around the screen (like Hisako). Characters like Sabrewulf and Thunder can even cross through an opponent with their dashes, giving them tricky offensive options, while characters like Spinal and Riptor run forward instead of dashing.
One important feature of dashing is that backdashes are fully invincible from frames 1-7. This means you can use them as a means to escape an attack or throw from your opponent, such as when you are rising from a knockdown, but you will be vulnerable at the end of your backdash if your opponent is ready for it.
Blocking
Blocking follows rules familiar to Street Fighter players. Characters can block high by holding the direction away from the opponent, or block low by holding both down and away. Most attacks in the game are "mid attacks" that can be blocked either high or low, but certain attacks called "overheads" must be blocked high, while other attacks, typically crouching kicks, must be blocked low. Virtually all jumping attacks are overheads, and some characters can perform an overhead attack from the ground using a specific command.
As is the case with many 2D fighting games, your best plan on defense is to block low by default and then react to overheads and change to a high block, since overhead attacks are almost always much slower than low attacks. There is no air blocking in Killer Instinct; if you jump, you cannot block until you land, and you can be freely hit by opponents.
Even though it is simple to describe, blocking is very important in all fighting games, and Killer Instinct is no exception. One of the most common mistakes beginners will make is not blocking enough, and they will give away damage by trying to attack or jump in situations that do not warrant the risk. While playing defense in Killer Instinct is difficult, and you shouldn't try to block forever, choosing to block only rarely will end up costing you matches.