In addition to cosmetic hacks such as file replacement, modifications to the gameplay of individual games, shorthanded to mods, have become a widespread phenomenon within the hacking community. The first attempts at modding involved Brawl, with such projects generally being viewed as novelties, not unlike the modification of palette swaps for characters; outside of this, forcing the Wii to load such mods was considered difficult, requiring use of the now-inoperable Twilight hack. The increasing complexity of game play mods and the discovery of the Smash Stack exploit, however, caused the mods to develop considerably more attention with observers.
Brawl remains the most commonly modded game in the series, though some mods also exist for Melee, Smash 64, and Smash 4. A majority of mods for Brawl can be loaded through the Smash Stack exploit, though alternate methods for loading them are available; mods for Melee often require the use of applications available for The Homebrew Channel. 19XXTE, a gameplay mod for Smash 64, requires patching a ROM image of the game, while a variety of experimental mods for Smash 4 on Wii U make use of a kernel exploit built into the console's internet browser.
Within the hacking community, the base game is often referred to as vBrawl or vMelee as a contraction for Vanilla Brawl or Vanilla Melee; the term "vanilla" comes from a common terminology featured in the computing world.
Gameplay modifications for the games are intended to, as their name implies, modify how the actual gameplay works. Specific changes to the game depend on the preferences of the developers, as well as their ultimate goal. Brawl+, for instance, intended to make Brawl competitive by making its gameplay more similar to Melee, while Brawl- overhauls the physics engine and adds significant buffs to all playable characters. Despite the differences in final goals, gameplay mods are generally intended to reduce competitive inequality between characters.
In addition to raw gameplay, other portions of the game may be overhauled by developers to further change gameplay. The changing of stages is among the more common ways to do this; Brawl-, for instance, replaces the ordinarily over-sized Temple with a smaller, more condensed version. Outside of this, unpopular stages might be entirely replaced with others, such as how Project M replaces the highly non-standard Mario Bros. with a rendition of Fountain of Dreams from Melee.
Stages are not the only method to altering the gameplay of the individual games. While a relatively new trend, the addition of characters has become a possibility for those interested in gameplay mods. Project M notably added Roy and Mewtwo as playable characters after the absence of the duo in Brawl, while Brawl- added Pichu, Roy, and newcomer Waluigi to the game.
Outside of these gameplay changes, gameplay mods may feature a variety of cosmetic changes to Brawl. Some tracks may be replaced, particularly in the case of original stages, and some characters may be given palette swaps that reference works not previously featured in Brawl.
Due to the Smash Stack exploit and relative ease of hacking the Wii compared to the GameCube, modifications for Brawl are considerably more widespread than those for Melee, though a small, devoted hacking scene for Melee has developed. Because of the difficulty of hacking the Nintendo 64 and a lack of demand because of a smaller community, only one notable gameplay mod has been released for Smash 64. Gameplay mods for Smash 4 are currently unavailable, as the hacking scene for the Wii U and 3DS has not yet fully developed.
Notable gameplay mods
19XXTE is the first and most notable of gameplay mods involving Smash 64. Similar to the concurrently developed 20XX, 19XXTE is intended to assist players in training their skills for professional play in Smash 64, as well as adding various improvements for tournament play, such as allowing for access to ordinarily unplayable stages. The mod has notably seen use in Smash 64 tournaments, including GENESIS 3, the second largest tournament for the game.
The 20XX Melee Training Hack Pack does not feature any true modifications to Melee's gameplay; rather, as its name suggests, it modifies Melee's overall user interface to allow players to train their skills for professional Melee tournaments. Hacks, for instance, can allow players to flash differing colours to allow for practising of L-cancelling or allow for players to view hitbox data for the game's various characters. Other, minor hacks are also available, allowing for players to modify stages, use PAL versions of characters, or use unique costumes.
An extension of the 20XX Melee Training Hack Pack is the 20XX Tournament Edition. Developed by professional Melee player Dan Salvato, 20XX Tournament Edition features various hacks to streamline the mod's performance in tournament use, as well as other minor improvements, such as widescreen support; it also uniquely runs via hacked save data on a GameCube memory card, allowing for it to be spread through the standard software found on either the GameCube or Wii.
Balanced Brawl is unusual amongst Brawl mods in that it does not significantly alter the core gameplay physics of Brawl. In its attempts to make the game more balanced, it instead primarily focuses buffing and nerfing all the characters, as well as adding some universal nerfs, such as altering how ledges work in order to combat planking. In addition to its various character tweaks, some of the stages were also changed, though not to an extent seen in other mods; most stage hazards are still present, but instead are either weakened or occur less often. Likely as a result of its lack of immediately visible changes, Balanced Brawl was unable to find the popularity of other mods for Brawl, though it did attain a small niche composed of those who opposed the changes made by Brawl+.
While not officially abandoned, the last notable update for Balanced Brawl, version 3, was released in 2010, with only a 2011 bugfix patch for PAL regions being released since then. Because of the effectively ceased development, Balanced Brawl is generally considered to be antiquated. As its last version was based on the Brawl metagame from 2010, some notable developments are not reflected in Balanced Brawl, such as the emergence of Olimar as a top tier character, as well as the gradually decreasing dominance of Snake.
Brawl-, like most other Brawl mods, attempts to change the cast and physics of Brawl in order to make the game more balanced. As a farcical jab to the then-concurrent mod of Brawl+ and its careful use of appropriate nerfs and buffs, the changes to the characters and physics in Brawl- are intended by the developers to be absurd and over-the-top in comparison; Brawl-'s development has relied on the mantra of "if everyone is broken, no one is". Hitstun, for instance, has been drastically increased as to allow for combos that are much easier to perform than either Brawl or Melee and all characters now have the ability to wall jump. In addition, instead of giving characters a mix of appropriate buffs and nerfs to balance the cast, all the characters have been buffed to ridiculous levels and each given a plethora of new, very powerful options; Ike, for instance, can charge Eruption and store it, allowing for a powerful kill move. The mod is noteworthy for being the only major Brawl mod aimed towards casual players instead of competitive players, though the mod is still intended to have competitive balance.
Brawl- enjoyed considerable popularity and attention when first released in 2010, and it became the most popular Brawl mod among the fanbase in this time, due to its more obvious changes compared to Balanced Brawl and its less controversial changes compared to Brawl+; the game was even featured as a side-event at some Brawl tournaments, such as at Apex 2010. As Project M got farther into development and started releasing more complete builds, however, Brawl- would become eclipsed in popularity, though it still has a large, devoted cult following. Despite the diminishing popularity and lack of representation at tournaments, development for Brawl- continues to this day, with builds being released into 2016.
Brawl+ was the first notable gameplay mod available for Brawl, and it also became the first mod to develop its own tournament scene, though such tournaments were not recognised as official. The mod featured multiple tweaks to gameplay that would later be seen in most future mods; in addition to changing the physics engine, some stages were changed in order to make them fit the guidelines for legality within tournaments, and individual characters had various attributes nerfed and buffed in an attempt to reduce competitive inequality between characters. Despite popularising the concept of modifying the base gameplay of Brawl and even being featured as a side-event at some Brawl tournaments, Brawl+ was immediately controversial to some members of the community, due to the fact that most of its changes were seen by many as solely attempting to make Brawl play exactly like Melee, particularly in regard to changes to individual characters, such as Fox and Jigglypuff having become altered to make them almost identical to their Melee counterparts. Brawl+'s own staff became estranged and antagonistic towards each other because of controversies over the development and ultimate goal of the mod.
Development of the mod ceased in 2010, with version 7.0.3. Most of its staff moved onto Project M, a mod with a similar design philosophy to Brawl+, but with a more concentrated and slightly different goal. Today, Brawl+ is mostly viewed as a curiosity amongst Smashers who are interested in seeing how the hacking scene of Brawl first started.
Melee: SD Remix
Melee: SD Remix is the first of notable of hacks involving Melee. While hacking the GameCube is comparatively more difficult than the Wii, the hack still holds some niche appeal amongst some devoted Melee players. The concept behind Melee: SD Remix can be compared to that of Balanced Brawl; both mods avoid making changes to to the game's base engine in favour of buffing and nerfing individual attributes of characters to make the game more balanced. Some stages have also been altered as to allow for better competitive gameplay. The development for SD Remix continues today.
Project M can be seen as a spiritual successor to Brawl+, due to the two mods sharing much of the identical staff. Project M features many of Brawl+'s previous physics changes, but was able to distance itself from the previous mod and its related controversies by giving more thorough changes to all characters. Of all Brawl gameplay mods, Project M remains the most popular, due to its altered physics engine that makes it play similarly to Melee and thorough nerfing and buffing of all characters in the game; although aimed primarily at hardcore players as opposed to casual gamers, Project M's considerable "fanservice", such as the inclusion of Roy and Mewtwo, new palette swaps that reference more video games than Brawl's standard selections, and other such interests have allowed it to reach popularity amongst such players. Project M's popularity led to it eventually becoming a notable side-event in tournaments, and it later developed its own distinctive tournament scene, with Apex 2014's Project M event attracting even more entrants than Brawl's.
Newer revisions of Project M had other additions to the game, such as added multiplayer modes, new maps, and a new announcer, with the last major revision being 3.6. While intended to include several completely new characters in its next revision, as well as further buffs and nerfs, development on Project M ceased on 1 December 2015, due to concerns over the legality of the mod. Despite this stoppage, Project M continues to maintain a devoted following, with tournaments for it still being organised.