Stunning Detail: Hitstun in Depth

Not sure if there’s much to talk about on this subject, but care to do a writeup on hitstun in videogames?

Hmmmm, yeah, there’s actually a bunch that could be talked about I think.

The big factors are interrupting attacks, advantage time, and pushback. Other things are knockdown, juggles, counter hits, meaties & multihits, special hitstun states, dizzy, recovery options out of hitstun, control during hitstun, hitfreeze, super armor, no hitstun, and blockstun.

The single biggest thing hitstun does to a game is it allows one character’s attacks to interrupt another character’s. This means a lot. It means that the first person to attack will win, which means you don’t always want to throw out an attack because your opponent might be attacking first. It also means you can’t just attack repeatedly, because eventually your opponent will interrupt you, assuming you can’t infinite them.

Advantage time or frame advantage is basically the difference between when you recover from your attack, and your opponent recovers from hitstun. If you recover first, then you are said to be plus on hit. This is noted as +# where the number is the amount of frames you’re up on your opponent. If you recover second, you’re minus on hit, noted as -#. Being plus means you get to act first, minus means you get to act second. The more plus you are, the sooner you can act, which means you have a higher chance of winning if both of you attack at the same time, and you can afford to throw slower moves since they effectively have less startup time relative to your opponent. If you’re minus then it means your opponent can act that way towards you. Going minus means surrendering initiative to your opponent. If you’re minus enough then it is even possible that you could be hit back by your opponent. Personally I consider it a flaw to allow a move to be minus enough on hit that you can be punished by your opponent. This is fine on block, but on hit it’s unacceptable. If you’re plus enough on hit to have enough advantage time to fit the startup of another move in, then that’s a combo. If you’re plus enough on hit or block to deny your opponent enough time to start up any of their moves, then that’s a frametrap.

Next up is pushback. Pushback is related to frame advantage because if you push something far away enough, then frame disadvantage becomes safe. I suggested with a theoretical 3d zelda that it should have low hitstun and high pushback, so you’re giving initiative to the monsters with each successful attack, but you’re never unsafe to their attacks. The more pushback there is, similarly it becomes harder to follow up when you get frame advantage. This can help keep combo systems in check.

A basic example of this is the smash bros knockback/hitstun system. In Smash Bros, attacks do a certain amount of knockback based on the attack strength and percent. The number of frames of hitstun is the knockback value times .4. This means you’re gaining more advantage as you push opponents further away. Eventually you have a ton of advantage time, but can’t catch up with them.

The exception to the rule in Smash Bros is meteors or spikes into the stage. These knock off 20% of the knockback, but keep the hitstun the same. So in Smash the general key to building combos is to at first hit opponents with attacks that have a quick recovery at low percent, then ones with good knockback and good recovery at mid percent, then ones with weak knockback to keep opponents close to you at high percents, then kill them with something really strong.

Knockdown isn’t generally considered a state of hitstun, but it’s pretty similar in a lot of ways. Players or enemies aren’t allowed to act during this state, and it’s generally harder to attack them. In some games they’re entirely invincible until they get up (dark souls, most fighting games). In some games they can be hit, but they take less damage and aren’t sent into a new stun state, effectively having super armor. In some games they can be combo’d off the ground by certain moves, which may have penalties to combo damage or generally be less convenient. In some games the attacking player is allowed to perform special finisher moves on knocked down opponents. In some games the player (or enemy) who is knocked down has multiple options for getting up, like rolls, or getup attacks. Knockdown generally serves as a longer special state of hitstun where opponents can’t do as much, and you can use them being knocked down as setup time to hit them when they get up.

Meaties are when you hit someone with the late part of an attack on purpose. In most games, attacks do the same amount of hitstun no matter what part of them hits, so hitting with a later frame of the attack means you get more advantage time. This is especially noticeable with rushing attacks where a character moves across space with a hitbox out. By hitting with the late portion of an attack, it’s possible to do new combos, or make attacks safe on block with good timing or spacing. Slow moving projectiles can have an effect similar to meaties at a range by allowing the user to recover and move up behind the fireball before it hits.

Multihits are related to meaties, because they’re kind of the opposite of them. Multihit attacks hit with many hitboxes over a period, each one dealing its own hitstun. Multihit moves get a consistent amount of hitstun no matter what part of the attack hits, but they keep the opponent locked down for their duration. This means multihit moves can never be unsafe by hitting with an early portion of the attack, and they usually go on long enough to give the player time to confirm they’re hitting. Fox’s dair versus falco’s dair is a good comparison for meaty versus multihit, except that Falco’s dair is one of the rare examples of a hitbox that stays out for a long period that actually decreases in hitstun the longer it stays out. Jigglypuff’s pound might be a better example.

Some games have special states for hitstun, like in some fighting games such as guilty gear, skullgirls, and third strike, you can hit your opponent reeling back, which makes them vulnerable to throws and command throws, which they normally aren’t during hitstun. Another example would be the dizzy state, where upon hitting an opponent enough, a meter fills up that when full causes the opponent to enter a prolonged state of hitstun, giving you enough time to set up whatever attack you want before they recover. If the opponent is player controlled, then usually they’re allowed to mash to speed this animation up. In Dark Souls, some bosses have special states similar to dizzy once they take enough damage, like the iron golem who can be knocked off balance, or a bunch of bloodborne bosses who will let you visceral attack them once hit enough. Some bosses also have tails that can be cut, triggering a special hitstun when they are. Guard Crush is similar, except it’s triggered when an opponent guards too many attacks, or has a specific guard breaking attack performed on them. This sometimes also awards bonus damage to the attacker (like in dark souls 1) or allows a special followup (dark souls 2 and 3). In the Souls games, The Last Blade 2, Nioh, Soul Calibur 1, and Guilty Gear Xrd you can parry your opponent to put them into a special parried state, which sometimes allows specific followups and in the case of Soul Calibur 1 and Xrd, they can parry you back during this state, at risk of being punished. Guilty Gear has a couple more special hitstun states in the form of the ground slide and wall stick. In some games you can set up special hitstun states that make the enemy weak to certain attacks, like freezing an enemy in metroid prime, then shattering them with a missile.

By far the best known type of special state for hitstun is juggles. Juggles are like an extended state of hitstun, except they have more timing involved than normal hitstun because you gotta time your attacks to hit the enemy on their way down. Juggles can be affected by enemy weight, gravity, or air drift. Juggles can have a lot of different potential trajectories and make use of things like ground bounces or wall bounces. Characters can even follow those being juggled into the air in some games to wail on them up there. The dynamics of a juggle are typically that you need to keep them in the air, or they simply fall into a knockdown or ukemi. Juggles are limited in some games by the natural ending of combos and progressive gravity. In some games characters are capable of “air teching” juggles to return to a neutral state. In God Hand, enemies will flip out of juggles at a slightly randomized angle.

Recovery options out of hitstun are relatively unexplored for most single player games except for the god hand example above. In a number of fighting games (smash, darkstalkers, marvel, blazblue, SFV) you can tech knockdowns to get up faster or roll in different directions. These typically have different amounts of invincibility associated with them. In God Hand, enemies can also block during normal hitstun, but cannot during counterhit/guard break hitstun.

In Bayonetta, enemies are allowed to attack directly out of hitstun, unless it’s a juggle or witch time. In many action games it’s possible to tech the landing or do a getup attack when you’re knocked down. The more recent soulsborne games let you roll out of knockdown, but have less invincibility on knockdown in general. Arc Sys games allow players to air tech from juggles, but the combo can continue if they don’t as an invalid combo. The Smash Bros example is interesting, because it’s possible to beat every option on reaction in what’s called the reaction tech chase. The option your opponent will go for is clear on frame 19 of the animation, allowing you to jab reset if they missed the tech, grab on neutral tech, and dash left or right and grab if they rolled. This might be an interesting avenue for a single player game to pursue in their hitstun design, allowing enemies different ways out of hitstun that sit at the periphery of human reaction time, so you can follow up your combos if you react perfectly. This could keep combos more active and engaging. Some attacks in some games can deal “hard knockdown” which is untechable.

Hitfreeze or hitstop, or hitpause is a short delay that happens at the moment of impact to both the attacker and target before hitstun plays out. In most games this isn’t very serious. In Smash bros you can actually jiggle and move yourself around during this period. In a lot of older games hitfreeze is applied instead of hitstun and only to the damaged enemy. Meaning that hitting an enemy will temporarily freeze it, but will not interrupt what they were doing. This can have a hitstun-like effect, but since it does not interrupt the enemy’s action, you are more vulnerable to what they do. This works well in older games and ones styled like older games because they were more about enemy movement patterns with collision damage on touching you rather than telegraphed attacks, so you can attack them to freeze them temporarily and hold off their assault for a bit in something like a pseudo-combo. The bottle in Castlevania 3 inflicts so much hitfreeze it can stunlock enemies.

Super armor allows characters to ignore hitstun, especially if it’s only for one hit, or below a certain threshold. In most fighting games, super armor works per-hit, so you absorb a certain number of hits before taking hitstun. Skullgirls is a notable exception, as well as smash bros which has multiple types of super armor that all do not follow the per-hit rule, knockback threshold and knockback subtraction armor. Armor that can take an infinite number of hits is called heavy armor. The souls series came up with their own concept of armor called poise, turning hitstun into something similar to a dizzy meter. Once the invisible poise meter is depleted, the target will take hitstun until the meter refills, and the combo ends.

Some attacks, particularly ranged attacks, deal no hitstun, like fox’s lasers and FANG’s poison ball. This is kind of interesting for low startup low damage attacks in systems that normally have hitstun (unlike say FPS games which do this, but don’t normally have hitstun, so there’s no contrast there).

In some games, like most modern fighters after SF3, counterhits, meaning attacks that interrupt an enemy’s startup or active frames, deal extra frames of hitstun. This means that new combo options open up if you can interrupt an opponent’s attack. This is primarily useful for frametrap strings, because the intent is to catch the opponent mashing buttons during the string, at which point the frametrap suddenly becomes a combo and it can serve as a confirm into a longer sequence. In God hand, counter hits carry special hitstun and juggle properties depending on the move. In SFV, certain normals can crush counter opponent’s attacks for bigger combo damage. In Souls games counter hits have no special effect on hitstun, but deal more damage. In Blazblue there are Fatal Counters and Counter Hit Carries. Fatal Counters add 3 frames of hitstun to every subsequent attack in the combo, making comboing off any move more easily. Counter Hit Carries are a property of most multihitting moves, making every single hit of the multihit a combo so there’s frame advantage at the end of the multihit sequence on the last hit, making it more easy to combo off that. In SFIV the level 1 focus attack will cause crumple on counterhit (another special extended hitstun state).

Blockstun is like hitstun except obviously you block the attack. A lot of the same rules of frame advantage apply, though the rules for what you can do out of block may be different per game, like in Smash it takes 15 frames to drop a shield, however you can grab out of it or jump out of it immediately, and your opponent is almost always negative, so the different options out of shield can be a big deal. In games like dark souls, different shields have different amounts of deflection, inflicting special recovery animations on opponents who attack. This is also found in Last Blade 2 for sword attacks versus punches or kicks. In some fighting games there are special blocks like instant blocks in guilty gear which reduce the amount of blockstun taken so attacks can be more readily punished on block, or faultless defense which increases the amount of blockstun along with pushback and prevents chip damage. Smash has similar to the faultless defense with its light shields that increase blockstun and pushback, also its perfect shields which can be canceled directly into actions or in later smash games negate shield drop time.

I think that’s everything I can say on hitstun. All of these are different factors that can be tweaked, tuned, combined, or experimented with to make different effects.

Saurian Dash did an amazing exposition on hitstun states for Transformers Devastation that shows some of how this information can be applied practically to a game. He calls these hit reactions, and later refers to “hitstun” as a special type of hitstun, akin to dizzy in fighting games.

This video shows how hitstun states can be varied between enemies to give them variety.

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