List of flaws in artificial intelligence (SSBB)

In Super Smash Bros. Brawl, the AI is generally more proficient with character recoveries, most prominently Luigi. If a human player gets an item like a Starman, rather than just trying to avoid that character, they will also use the opportunity to attack any stragglers. When a Smash Ball appears, computer players will aggressively attack it at opportune times, while repelling anyone who tries to get it as well. They also recognize and use all items as well, unlike in Melee.

Additionally, CPUs can now properly charge up or hold smash attacks and special attacks, among others, and choose more alternatives when using certain attacks, such as Kirby spitting out characters more often, Link using his grab aerial and the second hit of his forward smash, Marth using other variations of Dancing Blade, and Peach mostly auto floating to use aerial attacks against grounded opponents; they will as well try to reflect or absorb any projectiles they can with their special moves, and actually use counterattacks against foes instead of just ignoring them. CPUs can now properly use aerials to attack grounded foes rather than just attacking from land, and will always punish attacking opponents with shield grabs when possible, rather than just rolling away or dropping their shield after defending from an attack like in previous games.

Their taunting habits are less flawed than in Melee, as they don't use them if there are other enemies or obstacles, and they won't taunt if the player just escapes from them after they respawn (though they are now burlier than before, taunting even if their foe just self-destructs).

Additionally, CPUs in Brawl are much better at defending, as they sidestep and roll more often, and, with the change of air dodges, also use this technique properly, as well as being almost impossible for a human player to break a CPU's shield, and high-level CPUs almost always teching on any solid surface when launched a far distance. Plus, when a Hammer, Superspicy Curry, Starman, dangerous Poké Ball Pokémon or Assist Trophy, or Final Smash is being used by a foe, high-level CPUs will stay on their revival platforms if they were KO'd, instead of just reentering the fight instantly like in the previous games.

Another notable change is that, when a high-valued item appears, instead of just ceasing fighting to go for it, CPUs now try to repel any other character trying to get it, and if it appears too far from them, they will just ignore it and battle as usual (except for the Smash Ball).

A new feature in Training Mode allows the computer's level to be selected. The AI is improved greatly, as opponents set to Attack mode will actively fight the player, rather than walking towards them and rarely throwing an attack like in previous installments. Other CPU modalities can also be improved by raising the AI level. For each CPU level, the game gives an adjective to describe its skill, from levels 1 to 9: Puny, Wimpy, Weak, Normal, Hardy, Strong, Burly, Mighty and Nasty.

The flaws in Brawl's artificial intelligence are considerably lesser and less recurrent than in Melee, but they can still be potent. Computer players still tend to be easier to KO and edge-guard than the average human player, even when set to level 9, due to not utilizing survival techniques such as DI and usually not fighting back when being edge-guarded. CPUs do, however, air dodge when sent flying, which provides minimal cushioning for knockback although usually not enough to save them. Computer players sometimes have difficulty avoiding certain stage hazards (most notably on Halberd), and are prone to self destructing in scrolling stages, such as the Melee Stages Rainbow Cruise and Big Blue. They have generally poor edge-guarding abilities (though unlike the previous two games, self destructing while attempting to edge-guard is very rare), and will usually stand on the ledge and spam projectiles when the player is recovering; they will usually attack offstage intentionally only with characters that have multiple jumps, such as Meta Knight. And while they are better at recovering than in the previous game, computer players still underutilize recoveries, such as by not making use of alternate recovery options with some characters, or always recovering in the same direction with a recovery move. A computer player (regardless of level) will also always aim for solid platforms that can be sweetspotted when recovering, even when there are "soft" platforms off the stage.

Computer players additionally tend to play strangely in complex custom stages, and in overly large and complex stages like New Pork City and 75m, where they might stand in a place attacking nothing, or unintentionally self-destruct navigating platforms and hazards. And, despite recognizing items and using them better than in the previous installments, they may still self-destruct with certain items, such as by walking into a row of Bob-ombs when approaching a player, self-destructing with their own explosives, or inadvertently attacking a Blast Box and being KO'd by it. They still seem to ignore when Team Attack is on, continuing their assaults even when allies are in harms way as though Team Attack was off, which can cause them to hurt or even KO their own allies.

Aside from being flawed as stated above, in Free-for-alls, CPUs will all target the human player even if they aren't teamed. They will also target the character that has the highest damage to earn a KO, and in doing so will not attack other CPUs, which results in them following each other in lockstep.

Specific examples

Specific examples of poor AI include:

General

Category	Description	Character
Recovery	CPU Ness and Lucas will always hit themselves with PK Thunder in the same upward diagonal trajectory when recovering, even if using such a trajectory will result in them failing to make it back to the stage while a more desirable trajectory would allow them to recover successfully. This is especially noticeable on Final Destination, as Ness will often not make it back to the stage when using PK Thunder to recover (when recovery is possible), while a Lucas will often launch himself underneath the stage's lips. CPU Lucas will also never use his grab aerial for recovery.
	CPU Ike will not use Aether unless he is directly underneath a ledge. This can cause him to self destruct without trying to recover, or waiting too late to use Aether and failing a recovery that was possible. CPU Snakes exhibit similar behavior using Cypher, often choosing to use it too late and self-destruct.
	CPU Yoshi will never use Egg Throw for recovery.
	CPU Luigi will never use Luigi Cyclone for recovery, and never rise with the move in any other situation.
	CPU Kirby trying to get back to the stage while above ground level will nearly always repeatedly use forward aerials after midair jumps until he gets back to the stage; while this makes the CPU harder to edgeguard, the whole process still eventually becomes easy to predict and counter.
	CPU Meta Knight will never use Mach Tornado nor Drill Rush for recovery, and will often use Dimensional Cape to recover instead of Meta Knight's other superior recovery options.
	CPU R.O.B. will not input any actions after using Robo Burner until he reaches the ground, grabs a ledge, or is hit by an attack.
	CPU Fox and Falco may use their up specials in an angle towards the foe if they are offstage, even if it results in missing the ledge and self-destructing.
	If CPU Mr. Game & Watch uses Fire and fails to recover, he will repeatedly use Judge until the bottom blast line is crossed. While not necessarily problematic, there are instances where if a CPU Mr. Game & Watch reaches the apex of Fire and ends up short of the stage but in distance of reaching the ledge, the CPU will decide to use Judge too soon, causing him to miss the ledge and self-destruct.
Shielding & Dodging	If a CPU KOs a player, while the player has invincibility frames after respawning, the CPU will run away from the player and jump onto a platform if there is one nearby, without trying to dodge the player's attacks. On stages without platforms like Final Destination, CPUs will instead constantly roll towards the nearest edge, even when jumping or sidestepping are better options to dodge foes, making them predictable and punishable.	All
	High-level CPUs will almost always air dodge as soon as possible when launched a moderate distance, which can be easily exploited to get followups.	All
Other	When players grab the ledge, CPUs will stand still a safe distance from the ledge for some seconds before pursuing the ledge hanging player.	All
	If a CPU, regardless of level, is hit near the upper blast line while above an elevated platform, they will fall straight down until reaching the ground after knockback is finished, while making no attempt to dodge or counterattack a pursuing player.	All
	When hit by an electric hitbox, a CPU may randomly DI up or down, more often DIing down, which can result in instances of an attack with an electric hitbox KOing them when the computer player would have survived otherwise.	All
	While CPUs in Melee could meteor cancel to a moderate degree, CPUs will never meteor cancel in Brawl, sustaining the meteor smash's full knockback before attempting recovery. This results in meteor smashes KOing computer players at much lower percentages than they KO human players.	All
	CPUs that launch an opponent a significant distance upwards will just stay on the ground waiting for them to come down, spamming up tilts and up smashes as they get near, which can be easily dodged, even when going airborne and responding with aerials is a better option.	All
	When grabbing edges, CPUs will frequently choose to jump from them instead of using other superior options, like getting up with a roll or edge hopping, causing them to be easily punishable.	All
	When the player and a CPU with a chargeable projectile are on opposite sides of a stage, the CPU will often start charging and firing the attack, regardless of whether the player can absorb or reflect it.	All
	CPUs will never attempt to edgehog if they're on the stage; they won't leave the stage to grab a ledge to prevent another character from grabbing it. They will, however, remain on a ledge if a recovering character is also trying to grab it, but only if the CPU in question was attempting to recover as well.	All
	Only few AI-controlled characters, like Mario, will leave the stage to intercept a recovery with an attack (normally a meteor smash that's a forward aerial). Other characters with meteor smashes that are down airs, specials, etc. will only use them if they were previously away from the stage. On the whole, CPUs rarely ever attempt edgeguards, even if they have projectiles optimal for edgeguarding.	Almost All

Character Specific

• CPU Bowser and Charizard will never hold Fire Breath and Flamethrower respectively beyond their initial length. Additionally, they will normally attempt to B-reverse these moves after a jump, leaving themselves vulnerable to any attacks.
• When Snake uses his down throw near an edge on a CPU, the CPU will always roll toward the nearest edge the instant they can make a move. This allows him to infinite them or get an easy KO with an up tilt. When done in a soft platform without grabbable edges, they will instead always use a floor recovery attack.
• After using Gyro, CPU R.O.B.s will often continue to spam the move even though they cannot use it until the disc fades away.
• If a CPU Snake plants a C4 sticky on an opponent, he will always move a small distance away and use Cypher, then detonate the C4 after. This makes them extremely vulnerable, predictable, and punishable. If attacked out of the Cypher, they will simply run away a short distance and then detonate the C4.
• When Ganondorf uses Flame Choke on a CPU, they will never act the soonest they can.
• A low level Fox, Falco or Wolf will mostly self-destruct when using Landmaster, especially if the target is hanging on a ledge. A high level CPU will stay in place and repeatedly perform barrel rolls against opponents grabbing the ledge. Also, regardless of the level, they won't attempt to Star KO enemies above them by rising, only doing it accidentally when rising on small stages like Flat Zone 2.
• CPU Ice Climbers and Ike will often buffer their down aerials near a ledge, leading to them self-destructing.

Item Related

• When a CPU Luigi uses Negative Zone, he will almost always spam Fireball, even when set to level nine.
  • Similarly, a CPU Pit using Palutena's Army will spam Palutena's Arrow.
• CPU Sonics, Yoshis, or Diddy Kongs using Super Sonic, Super Dragon, or Rocketbarrel Barrage, respectively, have the tendency to behave rather eccentrically:
  • They will mostly avoid pursuing players who are hanging onto ledges or in hard to reach areas.
  • They may get stuck against a wall while chasing human players, and stay there until the effect ends (unless the player(s) they are pursuing jumps or moves to another area). Occasionally, they will manage to get off of the wall on their own and continue the chase.
  • They may stand still if the player is not within easy reach. Whenever they do this, they will only move if the player does.
  • They may even stand still when on top of slippery or fragile platforms.
• When trying to approach an offscreen item, a CPU will slowly walk against it instead of just picking it up.
• CPUs with a Gooey Bomb or C4 stuck on them will repeatedly shield and dodge until it falls off or explodes.
• Despite their better recognition of items, CPUs still experiment several flaws when using the Hammer, as in Melee. They still tend to accidentally fall offstage when trying to attack a foe near a ledge and, when on an elevated platform, jump continuously in place even if the obstacle can be jumped over. This is however less common with the Golden Hammer. CPUs also still chase foes when using a Headless Hammer or Golden Squeaky Hammer, and will try to avoid players with such Hammers instead of attacking them.
• CPUs exhibit several problems when using a Cracker Launcher. They will usually not turn around while holding the item, and they will not drop the item if it still has ammo. Additionally, if their targeted player is not directly in front of them, they will usually fire the weapon off at a slow, constant rate without changing their trajectory, and step back between each shot.
• CPUs holding a Team Healer will always throw it towards their enemies and never towards their own teammates.
• CPUs will never intentionally pick up Bob-ombs.
• CPUs will throw Deku Nuts at opponents regardless of distance, even if the opponent is close enough they will get stunned themselves. The same applies to Smart Bombs, where they will often throw them too close and get caught in the explosion.
• When a player is crouching behind an Unira, a CPU will always try to walk into it before attacking, resulting in them taking damage repeatedly until the Unira disappears.
• CPUs that pick up a Capsule will almost always throw it upwards into the air, in an attempt to break it as it lands again, even when throwing it down or just forward is a faster option for doing so.

Stage Related

• In stages with walk-off blast lines, CPUs will usually attack players near them without caution, likely causing them to self-destruct when overextending their approaches against them or trying to dodge their attacks.
• In the underground version of Mushroomy Kingdom, CPUs will repeatedly attack the blocks, usually ignoring the player even if items aren't on.
• On Delfino Plaza, when the main platform reappears and starts to rise, CPUs will usually stay on the old stage, which leads to them being lowered towards the lower blast line to their deaths.
• CPUs have a difficult time getting out of the underground part of Temple when opposing players are on the upper part. This is especially noticeable with CPU Wolf.
• CPUs will never swim on Pirate Ship or Delfino Plaza, always jumping out of the water immediately to come back to the stage.
• On Skyworld, CPUs tend to aim for the moving platform below the stage when recovering, even it it's moving away from them, often causing them to fail their recoveries when they could have aimed for the stage's ledges instead.

Rumors

Many rumors have circulated about the AI of Brawl. One rumor claims that level 9 CPUs read button commands the player inputs, thereby allowing them to perfect shield and air dodge more often. This sparked general dislike among the community, many of whom labelled the idea as "cheating". There has been no evidence however that the AI reads the player's inputs, and "evidence" presented for it has just shown that the AI has 1 frame reactions.

Another rumor claims that there is a system in Brawl that enables AI players to "learn" from human players. Nintendo Dojo blogger Churro Emiliano documented much of this widely for the first time in a blog post made at the end of 2008. Aside from some advanced techniques (such as dash dancing and DACUSing) and play-styles, the AI have also been reported to "learn" to taunt a KO by crouch-spamming, and to overuse Falcon Punches after humans play several Falcon Punch free-for-alls. This rumour is demonstrably false for several reasons:

• The AI code has been disassembled and examined during hacking (such as when KingClubber made changes to the AI for Project M) and no evidence of any learning mechanisms have been found.
  • Disassembling a Brawl save file also reveals that no AI traits are retained in the save.
• Despite the existence of videos showing the AI having supposedly learned various techniques or strategies, the AI will never under any circumstances learn to perform many actions (all actions documented in the "specific examples" section above exist in the AI regardless of the save file being played).
• There are save files in existence which have logged several hundred hours of versus matches against CPUs, but they do not have any clear, objectively measurable differences in their AI to other save files.
  • This applies to both differences between fresh save files that will not have had the opportunity for its AI to learn and to save files with AI which, if the rumour was true, have learned from different players and therefore developed a different playstyle.
• If the rumour was true then replays would desynchronise when the AI learned from the player and changed its behaviour after the replay was saved. Replay data does not contain the inputs of the AI; it contains the player inputs, information such as the stage and characters used, and the random seed of the original match. When the replay is played back, the AI determines its actions from scratch in exactly the same way as it did in the original match (the same actions are produced because all variables that would affect the AI's decisions are identical). The replay data has been disassembled to reveal that it does not contain any information about what the AI had learned at the time the match was saved. A learning AI would make different decisions in the replay than it did during the original match, causing the replay to desync, as it would be using its current behaviour (with the adjustments it had made after the original match) and not the behaviour it used in the original match.
• No documented objective tests (for example, only using one move in several matches on a fresh save file and seeing if the AI uses that move significantly more than on a save file which has been used normally) have been performed which have concluded that the learning mechanism exists.

See also

• Flaws in artificial intelligence