Buff

A buff is a term used to describe the improvement of a character (or aspect of a character), either through updating a game or by releasing a sequel. Buffs are often done as an attempt to balance the roster, by strengthening characters that are too weak; however, buffs can also be inadvertently added if a character is indirectly strengthed by an external gameplay change. Buffs contrast with "nerfs", which involve the weakening of a character or aspects of a character between sequel games and game updates.

Universal Mechanics

 * Every character now has four throws and specials with every character gaining an up throw, a down throw and a side special. Some throws and specials from the previous game has been remapped to these new moves. Up and down throws give multiple characters the ability to chain grab or tech-chase their opponent while side specials can grant characters an additional recovery option, a new defensive option, a new projectile or simply just a new attack.
 * Additionally, and  now have a grab aerial; which they can use as a extra attack or as a additional recovery option.
 * Air dodges have been introduced where the player can dodge in the air into any direction they want to. This not only gives everyone a defensive option in the air but it also gives characters an additional recovery option. When performed diagonally into the ground, it will make the player slide across the ground known as wavedashing. Wavedashing gives characters an additional movement option on the ground which especially benefits characters with low traction; most notably.
 * When the player lets go off a ledge, it will no longer cancel the intangibility gained from grabbing the ledge. This allows multiple characters to safely stall at the ledge with being the character who can abuse it the most. The player can also quickly waveland onto the stage after getting off the ledge which can allow them to perform many of their moves while still being intangible with  and Luigi being two characters who can solidly abuse this.

Character-specific

 * Jigglypuff significantly benefits from Melee's universal changes and its aerial mobility has been significantly increased; with its back and forward aerials also having less ending lag. These changes make Jigglypuff's Wall of Pain much more effective than it was previously. Rest has also received a significant increase to its already extreme strength and Pound has become a much more effective stalling option. A mid-tier character in Smash 64, Jigglypuff is now considered among the strongest characters in Melee.
 * As previously mentioned, Luigi immensely benefits from the addition of wavedashing, improving his previously unreliable and unsafe ground approach from his poor traction. Luigi also has better frame data overall and he has gained new combo starters such as his down smash, and neutral aerial. Considered the worst character in Smash 64, Luigi jumped to the mid-tiers in Melee and commands a sizeable playerbase.

Universal Mechanics

 * Most returning veterans have increased aerial mobility improving their recovery and making them less vulnerable to aerial pressure.
 * Air dodges have been changed. The main changes are that they cannot be angled and no longer cause helplessness and they can now be performed out of tumble. While wavedashing can no longer be performed due to these changes, this also makes air dodging a much stronger defensive option especially when combined with their reduced landing lag.
 * Due to the introduction of hitstun canceling, momentum canceling can also be performed. This allows many characters to survive longer with being the character who can abuse momentum canceling the most.
 * It is now possible to cancel a dash attack into an up smash (known as Dash attack cancelled up smash). This allows some characters to cover a great distance when performing their up smash, making it an excellent approach option for some characters. and  are two veterans who can particularly abuse DACUS.
 * It is no longer possible to DI moves which do not cause tumble. While this is rather detrimental for certain characters, it also allows for inescapable chain grabs and it allows various moves to chain into themselves more reliably. is a character who particularly benefits from this change as it gives Pikachu access to inescapable zero-to-death chain grabs against certain characters while not making Pikachu too vulnerable to chain grabs itself.
 * Shield stun has been reduced overall and most shield drops now only take 7 frames to complete (down from 14 frames). This makes shielding a stronger defensive option and dropping shield to punish moves is a much more viable option. Powershielding is also more effective as it reduces shieldstun and shield pushback even further and it no longer reflects projectiles which benefits Falco in particular.

Character-specific

 * To ail his status as the worst character in Melee, the changes in physics reduces Kirby's vulnerability to combos, and several of his moves have higher priority, damage, and KO power. The ability to grab ledges from behind via double jumps also aids Kirby's recovery, significantly reducing the already low difficulty of him returning to the stage. His air speed is also faster.
 * 's ground approach, manuverability, and getaway options were all significantly improved by the introduction of Quick Attack cancelling. Furthermore, buffs to Pikachu's forward and down throws gave them powerful chain-grab potential, especially against fast-fallers; adding to this, Pikachu's grab range was buffed from Melee, where it had commanded among the lowest grab ranges. Initially a high-mid tier character in Melee, Pikachu is considered a high-tiered character in Brawl.
 * 's defensive options were significantly buffed in Brawl, with a larger shield, increased falling speed relative to the cast, higher weight, and new access to momentum cancelling via Oil Panic. Initially suffering one of the worst survivabilities in Melee, Mr. Game & Watch is surprisingly difficult to KO in Brawl; coupled with improvements to his ground game, Mr. Game & Watch went from a bottom tiered character in Melee to a solid high tier character in Brawl, with early tier lists ranking him as among the best characters in the game.

Brawl to Smash 4

 * In the transition, a majority of veterans were overall nerfed in terms of their movesets (especially higher tiered characters) however, the game's universal gameplay changes have significantly benefitted most of the cast resulting in a fair amount of characters being stronger overall even if their toolset is weaker overall.

Universal Mechanics

 * Most returning veterans have had their dash speeds increased.
 * Fast falling speeds have been increased across the board; making many characters harder to juggle.
 * The effect of hitstun cancelling and DI have been significantly decreased. This has greatly improved the combo potential of many characters with some examples being, , and.
 * The effect of SDI has been reduced which makes many multi-hitting moves considerably more reliable and difficult to escape.
 * Edge hogging has been replaced with ledge trumping; which has made recovering much easier and has made edge-guarding much harder. The only option a player has to stop their opponent from grabbing the edge is to hit them during the first two frames of their ledge grab animation which is more difficult and less consistent/effective than edge hogging. This especially benefits characters who had rather poor recoveries in the previous game.
 * Rolls and especially air dodges are noticeably faster. Air dodges in particular have less startup lag and much less ending lag; making them easily spammable in the air. This further improves each character's recovery and ability to escape juggles.
 * Chain grabbing has been removed. While this hinders some characters, it also greatly benefits other characters such as and Sheik.
 * Rage has been introduced where moves deal more knockback as a character's percent increases. This enables players to KO earlier if they themselves are at KO percent. This particularly benefits heavyweights who can easily build up a lot of rage as well as characters who have powerful ladder combos and moves with very high set knockback such as Mario,, , and . These characters can potentially KO their opponents as low as 0% if they have enough rage.

Character-specific

 * has greatly benefited from the game's universal changes, restoring his previously powerful combo ability in Melee, including set-ups into his Knee Smash due to his altered up aerial. Along with this, buffs to the distance granted by his dash grab also grant Captain Falcon a variety of new combo starters; general increases to his range also made Falcon's approach safer in Smash 4 compared to Brawl. The reworked ledge mechanics also buff his recovery, which was previously considered among the worst in Brawl. Considered one of the worst characters in Brawl, Captain Falcon is generally seen as a high tier in Smash 4.
 * Of all characters, is generally considered to have been buffed the most. The game's universal changes greatly benefit him, granting him a much more powerful combo game that the opponent can't escape from. His aerial mobility has also been improved significantly which gives him a much better recovery when combined with various universal changes. With these buffs, he is usually seen as a top tier or at the very least, a high tier.
 * also significantly benefits from various universal changes, which benefitted his ability to setup and finish combos, most notably through PK Fire and his down tilt. Ness' forward aerial also connects better and is a greater combo tool due to universal changes; allowing it to easily chain into itself at low percents. His grab and throw game are even more effective due to various universal changes. Ness' grounded grab release also has reduced ending lag to match the rest of the cast; removing many grab follow-ups that could previously be performed on the character. A low-mid tiered character in Brawl, Ness is now considered a low high-tier character in Smash 4 
 * Due to her separation from, has gained a new down special known as Bouncing Fish. This new down special gives Sheik a new recovery option and a new KO move; offsetting two of her more notable weaknesses in the previous game. Her air speed is also much higher which also significantly improves her recovery and general mobility in the air. Sheik greatly benefits from the game's universal changes overall with her combo ability being considerably expanded upon and her altered forward aerial has made it an effective combo tool. Initially a low-mid character in Brawl, Sheik is widely considered one of the best characters in Smash 4 albeit to a lesser extent than in earlier versions of the game.
 * was significantly buffed due to his KO power being noticeably increased. He now has more KO moves and he overall benefits from the game's universal changes. His multi-hits are more reliable/consistent and his combo game is greater overall. The game's universal changes also considerably aid his KO potential. He has gone from 22nd place in the Brawl tier list to 7th in the Smash 4 list. This also makes him the third highest veteran in the game, and his tournament results are still beyond average as of today.
 * 's mobility has improved drastically and his KO power has also been considerably increased. His up throw is also now a powerful combo tool (as of 1.1.3) which can even lead into an up aerial for an early KO. Bowser also greatly benefits from the inclusion of rage as it further boosts his already higher KO power and due to his extreme weight (which has been significantly increased), he can very easily build up a lot of rage. Considered a low/bottom tier character in Brawl, Bowser is now a solid High tier in Smash 4.

Smash 4 game updates

 * was significantly nerfed from Brawl, with less effective range, poorer frame data, poor approaching options, and a weakened grab game, resulting in a precipitous fall from the top tier in Brawl to the bottom tier in Smash 4. Updates however, slowly begun to improve Marth's and 's standing in the competitive community (especially after update 1.1.4), with said updates improving his frame data, range, damage output and KO power. His neutral attack in particular was significantly buffed. In later updates, it launches opponents vertically and received less ending lag; making it a powerful combo tool. With these improvements, Marth's previously small playerbase increased, and his standing in the metagame had improved significantly. He was ranked as a low tier on the first tier list although in the last two tier lists, he has regained his position as a top tier character.
 * While received some buffs in Smash 4 compared to Melee, such as improved strength and consistency in its aerial and special moves and speedier movement, Mewtwo was still initially considered a low-tier character in Smash 4, due to its poor approach and grab game in comparison to Melee; furthermore, one of Mewtwo's biggest flaws in Melee, its poor combination of being light, floaty, and large, was made worse in Smash 4. Updates, however, have improved Mewtwo's standing in the metagame, with its mobility being drastically increased as well as having improved frame data, KO power and survivability. Initially a low tier in Melee and early versions of Smash 4, Mewtwo jumped to the tenth position in the second Smash 4 tier list where it has remained for the past three tier lists.

Smash 4 to Ultimate

 * In transition to Ultimate, many veterans have been buffed significantly due to a vast majority of universal changes mostly because the game was reworked to speed up gameplay such as landing lag reduction, air dodge mechanics, and offensive plays.

Universal Mechanics

 * With the exception of, all returning veterans from Smash 4 have had their dash speeds increased.
 * All jumpsquats are now only 3 frames long. This gives all characters (besides ) access to their aerials sooner when they are on the ground; granting them more combo opportunities and making aerials more effective as an out of shield option. This especially benefits characters who had rather long jumpsquats in previous installments such as and.
 * Traction has been significantly increased across the cast with even the lowest traction values being greater than the highest traction values in Smash 4. in particular benefits the most from this change as his traction is no longer the lowest in the game like in all previous titles, granting him a better approach as well as a significantly improved out of shield game.
 * It is now possible to cancel a dash with any grounded move. This gives character's a wider array of approach options.
 * Grounded meteor smashes can no longer be teched like in Smash games prior to Smash 4. This generally makes meteor smashes more reliably combo tools (especially since most meteor smashes have reduced landing lag) as well as making them more reliable KO moves on stage.

Character-specific

 * as a whole received significant buffs through the tweaking and removal of detrimental character mechanics. Stamina is no longer a factor so Pokémon are no longer forced to change, or fight at reduced strength; type effectiveness has been removed so Ivysaur no longer suffers additional knockback from fire damage; Ivysaur's Vine Whip can no longer be canceled out by ledge hogging and Pokémon Change is much quicker and can be used in midair, giving it applications as both a dodge and a recovery mixup tool.
 * and arguably benefit the most from Ultimate's universal changes and mechanics. The nerfing of defensive options compliment their aggressive playstyle when compared to their parent character, and the universal mobility buffs, landing lag reductions, and ability to cancel a dash into any ground attack greatly improve their approaches and make landing the sweetspot of Roy's sword attacks easier.
 * Compared to other fighters, was one of the most buffed characters. Pichu's recoil, which is one of the big problems that caused its bottom tier status in Melee, was not only decreased, but also now benefits it with thanks to rage. Not only that, but its approach options are more effective, as Pichu's fast mobility has improved and it can now crawl. Not only do Pichu's electric attacks do more damage and less recoil, but it is now much heavier, although it's still the lightest character in the game. This, combined with its fast mobility helps Pichu fight better. Pichu was considered to be a top-tier in the early stages of the game, though it later got noteworthy nerfs through game updates which affected its viability, it nonetheless remains a strong character and drastically better than its Melee appearance.
 * 's zoning game has been significantly buffed in Ultimate. Her up smash lasts significantly longer and her neutral special Autoreticle covers more range. Her old side special has been replaced with Explosive Flame, improving her offensive game.
 * 's aerials have decreased landing lag, thus improving his frame data allowing for more guaranteed follow ups along with his buffed Monado Arts which can now be switched faster. Additionally, he can now use the advanced technique.

Ultimate game updates

 * was notorious for his poor performance due to the nerfs he received during his initial release. His Echo Fighter was slightly more prominent as he performs slightly better than him, though Ken was still regarded as low-tier. Possibly as a result of this, update 3.1.0 addresses several buffs that grants both Ryu and Ken even more combo potential. All of their moves were made to connect into each other much more fluidly such as their held attacks and longer input window.
 * Since the early metagame of Ultimate, was designated as a lower tiered character. His combo game was significantly nerfed, going from among the best to just mediocre. He retains his weaknesses in the form of his bad damage output, bad KO game, and poor recovery. This led to a negative reception where Diddy Kong was regarded as unviable. Luckily, Diddy Kong was heavily buffed in future patches, which made him fare better relative to the cast. Notably, Rocketbarrel Boost now recovers a further distance when charged.
 * 's frame data, along with other moves, has been reworked to improve his neutral game. Several of his moves include having less start up, less ending lag, increased range, damage, and significant armor. Overall, King K. Rool is one of the few characters to receive the most buffs throughout all game updates.