Perfect Play AI

What is it like to challenge a perfect opponent?

Perfect Play AI is a type of Video Game AI most commonly found in Fighting Games that correctly blocks or evades every attack and move the player is capable of performing against it, while slowly approaching the player to attack (often backing the player into a literal corner in the process). They were first popularized by the Mortal Kombat series, but have become a recurring AI type in other fighting games, which are often so Nintendo Hard that it seems unfair (even when the computer is not actually cheating), possibly even invincible.

The AI's attack strategy is actually quite simple, but excruciatingly effective: The AI has been carefully programmed to avoid making any "unsafe" actions that would provide a clear opportunity for a human opponent to damage them. This includes:


 * Correctly blocking and/or evading attacks which the player executes against it;
 * Never executing jump attacks, rolls, or any other movement that would obviously preclude it from defending against the player;
 * A full knowledge of the game's Tactical Rock Paper Scissors, such as which attacks can counter which moves (like using a Shoryuken to counter a jump attack, or a weak-but-fast jab to prevent a heavy punch or Unblockable Attack from executing);
 * If it posesses a Counter Attack move, knowing how to time these counters to maximum effect to trap and punish the player's attacks as often as possible.
 * Conversely, if the player posesses a Counter Attack move, the AI may know how to avoid falling victim to it.

It's important to note that, generally speaking, the Perfect Play AI is not technically cheating: All of the above moves and tactics are perfectly legitimate, i.e. a sufficiently skilled human player could perform such a strategy themselves to best their opponent. The AI's main advantage here is that Computers Are Fast, and it can execute these actions with split-second timing and pixel-perfect precision. Whereas a human opponent must visually deduce and predict what their opponent is about to do next, an AI can immediately and directly identify whatever action (movement, attack/defend, etc.) the player is currently performing, even if different moves have similar tells that would confuse a human player.

Of course, it's also possible that some Perfect Play A Is are also cheating bastards, but exactly how to distinguish whether or not this is the case is a difficult matter -- in games where Defeat Means Playable, a player can compare whether the character in question handles the same in the player's hands as it did in the AI's. For example, if a character has a special attack that requires holding "down" for a full second before executing, a human player is left vulnerable while preparing it (as they cannot move while crouched), but if the AI can execute it immediately with no preparation, then that is a sign of cheating bastardry. However, if the AI is a unique opponent, it may be impossible to ever determine whether the AI was actually cheating, or if the boss character was just Purposefully Overpowered.

There are few reliable ways to defeat the Perfect Play AI in a fight. One method is to relentlessly attack the AI with Combos and special attacks (ranged or otherwise) that utilize Scratch Damage even when blocked; this will slowly wear down the AI and defeat it via Death of a Thousand Cuts. Another method is to simply fight fire with fire: Memorize the AI's attacks over time and learn to perfectly block and/or Counter Attack whatever move the AI chooses to perform, which may create an opening (no matter how small) to strike back. Most Perfect Play A Is have a flaw in their AI routine somewhere, and once the player learns to exploit that to their advantage, the playing field becomes level.

If the AI takes the blows instead of blocking or avoiding them, it's the Implacable Man. If the AI doesn't seem to take any damage at all, then it's The Juggernaut.

Compare and contrast the SNK Boss, a videogame AI whose difficulty arises primarily from the fact that it is a cheating bastard.


 * Mortal Kombat is famous for this, this is why the trope used to be called MK Walker; an AI opponent on this mode would simply block or dodge any attack thrown by the player with inhumane frame precision and beat the player mercilessly, giving the impression that the AI was walking over the player.
 * Basically all Mortal Kombat II characters at hardest setting.
 * This becomes even more blatant in Ultimate Mortal Kombat 3, Mortal Kombat 4, and the N64 version of Mortal Kombat Trilogy.
 * Mortal Kombat 3 on the Game Boy has it too, but they're surprisingly vulnerable to uppercuts. Hope you enjoy doing nothing but uppercuts.
 * Shang Tsung can be murder for this; sometimes, in a single motion, the CPU will transform into a new character and perform the counter-attack that character knows.
 * Jade in Ultimate Mortal Kombat 3 deserves a special mention. When you play as her, the projectile protection special has to be activated by Back > Forward > High Kick command. When AI plays as her, if you try a projectile attack on her, most of the time she will activate the special at the exact moment you input the projectile move, while running towards you and without stopping at all, and then rip you a new one before you can block anything.
 * Smoke in Ultimate Mortal Kombat 3 is impossible even on Very Easy. If you send a long range attack or projectile towards him, he will instantly teleport uppercut you INFINITELY. Before there's even an animation, he's already killed you. When you play as Smoke, the computer instantly dodges teleporting moves.
 * The bosses of Mortal Kombat 9 are particularly notorious for being Perfect Play AIs. Especially Shao Kahn.
 * Not to mention employing No Sell whenever they feel like it.
 * ANY character from Kagemaru on in Virtua Fighter 2.
 * In Last Blade, the boss, Kagami, is a Perfect Play AI in his first form.
 * Then again this is a trait most SNK Bosses share.
 * Street Fighter's Zangief.
 * If you set the difficulty to the hardest level on certain Street Fighter II games, nearly every character becomes a Perfect Play AI. It's more proficient in Shotos and Guile, though, who especially like to jab faster than the speed of light. Also if you get caught in a hold throw, like Dhalsim's noogie or Balrog's head bash (that looks suspiciously like he's biting your ear), don't expect to escape anytime soon because they'll usually go faster than normal.
 * SFA 2's Shin Akuma on any setting and to a lesser extent SFA 3 Akuma on medium and up are terrible about this. His Perfect Play AI routine consists of walking psychic shoryukens combined with tick throws, the result being that you're afraid to poke with anything, because no matter what you poke with, or how you set it up, the comp will just read your buttons and DP you out of it. If you block, the computer will just tick throw you out of it. If you are expecting the tick and try to reverse the throw, you'll get psychic DP'ed (since you're performing a throw/attempt and not really blocking). Try to perform a reversal and you'll be thrown. Occasionally (and Ryu will do this as well, though not with all the other stuff Akuma adds in), if you get the reversal, Akuma will actually block, then throw a reversal DP on the tail end of yours.
 * Speaking of the Alpha series, friggin Final Bison in Alpha 3. With or without Final Psycho Crusher he's still incredibly annoying with this.
 * Let's not forget about Akuma/Gouki from Super Street Fighter II X/Super Turbo. On eight stars he becomes the cosmic overlord of this trope.
 * Street Fighter IV's Seth is an SNK Boss with this. It's fairly easy to beat him at first, but once you finish Round 1 he gets up and says "I Let You Win". Cue this trope in full force.
 * Kasumi Todoh in most versions she is playable in The King of Fighters. Her fighting style is based on returning physical attacks with her counter stances. If controlled by a Expert level CPU, she will slowly approach the player while instantly countering moves that make physical contact and doing a reversal uppercut if the player tries to do a normal grab on her. She also has a unblockable move that works like a grab, so if you choose not to attack her when she reaches you, she'll use that. A nice addition is that if you try to stop her from advancing with projectiles she'll just stop, wait a while until you stop throwing fireballs, and taunt you.
 * Killer Instinct. If you do any kind of move that has more than 5 frames and doesn't hit the opponent, the AI will rush in, do a special which goes straight through your attack, and then follow up with a flawless 8-hit combo. All at the exact moment you press the button. There's a reason we call Nintendo Hard "Nintendo hard".
 * Much less prevalent in Killer Instinct 2, where the game mechanics are much friendlier and give you many opprotunities to counter the AI. The Tactical Rock Paper Scissors nature of how combo openers work in KI 2 is probably the easiest thing you can use to this effect, and combo breakers are much easier, so the AI popping off its perfect combos is no longer your death knell. In fact, if you don't have the reflexes to do the breaker correctly on purpose, you still have a fifty-fifty chance of getting it by guessing.
 * In Real-time Strategy, something similar to a Perfect Play AI strategy is done by hiding most of the army around a cluster of long-range artillery units, then cascading them forward so that the army never leaves their protective shadow.
 * Starcraft's Terrans, with their Siege Tanks and generally low mobility, tend to thrive on this.
 * The rather difficult "bunker rush" is based on the same idea.
 * In the Advance Wars series an inversion of this is done by a tactic called 'mech spam', which involves using artillery shielded by lots of cheap infantry units with bazookas -- the enemy gets bogged down trying to chew through the infantry hordes and are cut to pieces by the artillery.
 * In real-life strategy this is called [[http://en.wikipedia.org/wiki/Barrage_
 * Several of the bonus bosses in One Must Fall, especially Devan Shell. To make things worse, One Must Fall had NO block damage.
 * All the arcade mode opponent on Ultimate difficulty probably count as Perfect Play A Is. Luckily they don't handle special move cancelling well.
 * Every opponent on every difficulty in Facebreaker.
 * Probably other SNKBosses, but Geese Howard from Fatal Fury fits this trope best.
 * The AI in Soul Calibur 3 can sometimes do this when it's going all out. It can read your buttons, and (when it's at its best, like on Dancing Statues Hard) it can counter moves with its inhuman reflexes. Worse, it gets faster based on how much you press the button, even blocking. So if you block too long, the computer goes into a berserk rage, conveniently attacking in a way that gets around your block and is simply too fast to counter.
 * Paticularly notable with Setsuka. Anything short of a one-hit-knockdown move will be countered with perfect precision, and long-range strategies are crippled because she is one of the faster (if not THE fastest) character in the game and the only CPU opponent that concentrates on Ring Outs. Player controlled Setsuka, however, is nowhere near this effective (thanks to human beings being forced to actually press buttons to set up some of her harder moves, which the CPU does not have to contend with, and thus can use them for juggling.)
 * Maybe YOUR player-controlled Setsuka isn't that powerful, but they're out there. And they want blood.
 * It should be mentioned that not blocking in multiplayer is a good way to get slapped around, eaten, regurgitated and then stomped on.
 * It's back with a vengeance in Soul Calibur 5. This troper has noticed that almost every AI character's actions in the Story mode are nearly flawless. Chapter 19's last round has been played about 30 times because Nightmare won't stop being perfect. He blocks nearly every hit unless doing so would inflict Guard Break, his Critical Edge is unblockable but he ignores the player characters, and when his connects, it does about 80% of the health bar, whereas the player's does about 15% of his. He employs stunlocks, juggles, and just generally acts like a good ol' MK Walker.
 * Vergil from Devil May Cry 3 acts like a Perfect Play AI "normally", as in he normally walks towards Dante while parrying any moves the player makes and counters immediately. The key is to let him attack first, dodge and counter. In this respect he is not a full-fledged Perfect Play AI.
 * Devil May Cry 4 has a number of examples:
 * With some of his styles, Dante does the same as Vergil from before. The most effective way to beat him is walk to him while shooting, causing Dante to do the same, then quickly attacking with Devil Buster once in range.
 * On Dante Must Die, Berial becomes like this. Going to face him head-on suicidal. The secret to beating him is to do these things: 1. Use your fully charged gun on him as much as possible. 2. Hit him with your sword immediately after he does a lunge attack. Go for the sides and hindquarters. 3. The moment his flames drop, go berserk with devil trigger, especially trigger-enhanced buster (Nero's demon arm).
 * The Angelo Credo fight is a good example of this trope as well. Most of the time, he will advance steadily towards you or hurl spears at you. His sword attacks are a bitch to dodge (so quick you don't see them), and unless you nail the timing, attempts to grab him will either fail, or do very little damage.
 * Some mooks also do this, such as the Angelo enemies. Alto Angelo will block your hits a lot and often your attempts at grabbing them result in a No Sell.
 * This can happen in tag-team matches in some games in the WWE Smackdown vs. Raw series. If a computer player decides that they want to tag out, then 90% of the time your every attack will be countered, dodged, or ignored until this is done. It usually does not occur in other modes, however.
 * If the computer does not want to allow you to do a flying attack it will stop you, no matter what.
 * Face it, the game will simply glitch if it has to.
 * The Final Boss of Zelda II: The Adventure of Link is an example that predates even the more infamous figthing (i.e. MK) examples: Dark Link aggressively advances toward the player and tries to attack whichever position (high or low) the player isn't currently guarding against; and when the player attacks, Dark Link merely counters with his shield in the appropriate position. He is remembered for having one flaw in his AI ("duck and stab") because he sometimes counters a low strike with a jump, which leaves his legs open to attack.
 * Dark Link in The Legend of Zelda: Ocarina of Time, being a Shout Out to the original, mirrors Link's sword attacks (almost) perfectly, causing nothing more than clashing blades. (Dark Link is also opposite-handed from normal Link, adding to the 'mirror' effect) He backflips to counter Link's charged spin attack, and if the player attempts to make a thrust attack, counters by jumping on Link's sword and striking. For the first half of the battle he doesn't even attack at all, but merely stands back and counters Link's moves. But he actually doesn't counter much else, such as bombs or Deku Nuts.
 * The Super Smash Bros Brawl re-enactment of this battle can echo this as well, especially on harder difficulties.
 * The two-player version of that fight adds Dark Samus, who knows exactly how to aim her missles to counter yours.
 * Speaking of Super Smash Bros Brawl, high level CPU Peach loves to hover right above your range as she approaches you. If you try to counter she can land prematurely and smash/Peach Bomber you, or she can air dodge, cancel it as she lands and beat you up anyway. Never mind when you fight Metal Peach...
 * Actually, that would probably be easier, since the metal adds weight, and unless it has a different AI specifically for metal, that will throw its oh-so-perfect timing off.
 * Valkyrie from Tales of Eternia. Not only is she an equal in close quarters to Reid, Farah, Ras, or Cless (the other Bonus Boss), she can guard-break you as well, interrupting any combo you initiate and opening her own routine. With flawless timing of course. Without Rising Phoenix or Sonic Chaos, it's impossible to hurt her. Oh, and she has her own hi-ougi too, and it is mean.
 * In the browsergame Estiah, the Chest Mimic is a turn based variation of this. This monster either uses 'Close', which gives it enough defenses to easily shrug off multiple attacks, or a few offensive moves which, despite stripping it of all defense, all give in an extra action (And unlike the player, the mimic is immune to the four action limit). This means that after hitting you a few times, the boss will always leave a wall of defense that is impossible to brute force through. However,.
 * In Eternal Fighter Zero, final boss Kanna fits this trope quite well at the higher difficulties. Her AI will block practically every attack you throw at her, and her range, attack speed, and priority will rock you when she gets close. Ayu also has some of this trait on the highest difficulty.
 * Chin fights like this in The King of Fighters '97. However, it's fairly easy to work around it by jabbing at a distance and blocking his attack.
 * As a boss character based on counter moves, Blaz Blue's Hakumen rather sensibly fights this way. If you're not careful, he may well counter you into a Astral Finish. Depending on your character and playstyle, he can make the game's actual SNK Boss v-13 feel weak and anticlimactic in comparison.
 * In Score Attack mode, everyone turns into Perfect Play A Is. Instant Blocking all your attacks and escaping your throws before launching you into a 20+ hit combo the instant you do something unsafe. And then you have to fight Unlimited Nu, Unlimited Rachel and Unlimited Ragna in this mode. And if Unlimited Ragna hits you with the right counter, he will super drain over 2/3 your life and heal over half his already 3 times over health bar.
 * Extend ups the ante with "Unlimited Mars" mode. Everything above, and EVERYONE is in their unlimited mode. The unholy fusion of SNK Boss and Perfect Play AI.
 * Arc System Works has done it again. With their help on the console port of Arcana Heart 3 in score attack mode, Parace L Sia returns, and combines this with SNK Boss into one of the most unholy fusions imaginable, making every unlimited character from Blaz Blue seem like nothing in comparison.
 * The Sega Genesis Teenage Mutant Ninja Turtles Tournament Fighters had Karai as the last boss. If you tried to stand back, she would spam projectiles you couldn't jump over. If you tried to get close, she would knock you down, then throw you repeatedly with absolutely no window of opportunity to move or escape between throws. This was at difficulty setting 1. It went up to 8.
 * She was much worse in the SNES edition. Air superiority in the form of a leaping multi-hit attack, similar to E. Honda's Hundred-Hand Slap, and she had the best jump in the whole game. She could easily clear most of the screen in one leap. And she "walked" rather fast. Trust me, she was bad, bad news.
 * The highest-level AI's in Dissidia Final Fantasy are made of this trope; they will easily predict and block or dodge almost any attack, while attacking instantly and fatally as soon as you get anywhere near them. Your only real chance is to block at random times, hope they do something blockable to you, and attack them instantly while they reel back (a time span which is, naturally much shorter than yours would be).
 * Saotome Genma in the SNES Ranma One Half Hard Battle.
 * WWE SmackDown vs. Raw 2010 has one of these, curiously enough for a wrestling game - the final fight in Edge's Road to WrestleMania story against Mr. Kennedy (KENNEDY!) sees Kennedy become an absolute perfect countering machine, who can recover from anything you throw at him in no time while being able to leave you lying with almost any grapple he uses.
 * This also happens in Randy Orton's Rt WM, as part of an Unwinnable Boss Fight; the lights go out and suddenly the Undertaker is standing right behind you. He is impossible to hurt, perfectly evading and reversing anything you attempt to do to him - and the objective changes from winning the match to escaping backstage.
 * In Day of Reckoning series, WWE games for the Gamecube, if the computer decides it's time to tag a partner, knock out the referee or go for a weapon don't expect to get any hits in. It will slowly walk to its destination as if there is a sunset in the background and counter every move you do even ones impossible to actually perform (e.g. countering a move while in the process of countering a move).
 * In Sid Meiers Pirates, on higher difficulty levels and age, the Marquis de la Montalban becomes this. He will always perform the proper defense for your attack far faster than you can attack, with the net result being that the fight is literally Unwinnable.
 * The optional second boss fight against in The Force Unleashed. He stops playing around with force telekinesis to demonstrate his mastery of lightsaber combat.
 * He's also kind of this in Starkiller's duel with him in the sequel. He's a Mighty Glacier that takes very little damage from all of your attacks, blocks all of your Force moves (even going into Force Fury mode only damages him a small amount) and he has two health bars.
 * The prologue level of the first game inverts this by having you play as Vader while he leisurely strolls through a Wookie village and nonchalantly massacres everything in sight.
 * Boss battles with Jeanne from Bayonetta see her acting relatively sedate from far away, usually content to pepper you with gunfire or launch a super-attack or two your way. However, she's always closing distance between Bayonetta and herself or waiting for you to come to her, and once the gap is closed she begins busting out lengthy and hugely damaging combos with very little breathing room between her attacks. On the harder difficulties, she drops this tactic and just starts tearing you apart from across the room.
 * Cyber-Akuma from Marvel Super Heroes vs. Street Fighter is a abnormally fast Perfect Play AI. His preferred method of attack is to launch a missile from a screen's distance, then dash in close as you block high, deliver a lightning-fast low kick and chain it into a super attack. When he air jumps, he unleashes 2 fireballs down at you. The only way to beat him is by piling on the projectiles but he readily throws his own to counter yours. If he closes the distance between you, it's pretty much over.
 * Several bosses and some Elite Mooks in the Streets of Rage series, fan remake included. Some foes will always back up out of your reach the minute you try to advance on them to attack (but will gladly advance on you the minute you turn and walk the other way), backing up off the screen where you can't hit them, but they can hit you. You also have enemies that will stop moving or sidestep your special attacks and will follow up with a counter. Then there are enemies that will knock you out of the air if you try to attack them with a jump attack. To top all of his off, most enemies in the later levels will combo you and team up on you where their attacks take priority over your own attacks.
 * Used to awesome effect by in Resident Evil 5. Walks forward menacingly, instantaneously flashstepping bullets and knife attacks . Also inverted, if you decide to fight him rather than time out the level; nearly all of his attacks can be brutally countered if you're fast enough, and his attacks very briefly leave him vulnerable to gunfire.
 * Agents from The Matrix can be thought of as Perfect Play A Is within that particular game. Any gun attacks are automatically dodged while they walk towards the humans, and generally their kung fu is so much better than yours that there's little chance surviving if you let them reach you. Supposedly, Neo could beat them because he could "read" the patterns in the code and counter the AI.
 * One "Boss" (all enemies operate the same way, but from the storyline some could be considered bosses) in Def Jam: Fight For New York starts out as this. You're supposed to avoid him until his ability wanes, but it is possible to counter all of his attacks.
 * In Super Cosplay War Ultra, Shin-Z is particularly adept at this. Manage to knock him down? He'll block as soon as he gets up to prevent a follow-up attack. Try to attack him from a distance? He'll start spamming high-priority projectiles non-stop to pin you down while he slowly advances towards you. Manage to jump over the projectiles and air dash in his direction? Genocide Cutter to the face. Manage to get right up next to him somehow? Enjoy an unblockable grab attack, that he'll usually chain into a super grab attack. Sometimes it seems like the only way to hit him is when he tries to use his super when he doesn't have enough EX bars for it, stunning him for a brief second (then again, this is a flaw with all the bosses in the game.)
 * In Metal Gear Solid: Portable Ops, Null does this on harder difficulty modes. If you roll at him at just the right angle, though, he swipes at you with his sword, giving you a window in which you can pump a tranq dart into him.
 * In Professor Layton and The Last Specter, a few puzzles feature an AI opponent, in cases in which you have to force the opponent to make the last move. The opponent will always make the ideal move under the circumstances, and you must make the right decisions to force it into a situation in which it has no choice but to be defeated.