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Melee based changes
The following mechanics have been altered to match their Melee forms:
General amount of freeze frames reduced.
All characters have faster falling speeds and gravity, and more forwards momentum from a dash is conserved when jumping.
Air dodging applies a directional boost and causes helplessness, making it generally riskier for midair combat, but allowing faster midair movement within short ranges and restoring the wavedash techniques vital for most characters' metagames.
L-canceling halves landing lag when a shield button is pressed 7 frames before landing, thus reinstating the SHFFL technique, bolstering characters' midair movement and allowing much better usage of combos. A brief white flash on the character is additionally displayed when an attack is correctly L-canceled.
Dash dancing's timing has been reverted, making it longer and more practical, and characters can shield during one.
Crouching cancels dashes, allowing quicker, more varied options after dashing.
Crouch canceling reduces knockback, and hitting the C-Stick down while crouching uses a down smash (in Brawl it used a down tilt), allowing to efficiently counter opponents by crouching.
Consecutive jabbing is removed.
Double jump canceling reimplemented; its usage varies slightly between characters.
Ledge teching reimplemented, again giving recovering characters the possibility to survive at ludicrous damages by DIing toward a ledge and teching into it upon being attacked. Ledge-canceling is once more possible as well.
Jumps can be canceled with grabs, so regular grabs can still be effectively used after a dash, avoiding the usual ending lag of a dash grab.
Powershielding can reflect projectiles during the first 2 frames.
Shieldstun formula reverted. Like in Melee, characters now also take longer to act out of a shield drop (almost twice as in Brawl), causing the gameplay to be less defensive-focused.
Ledges cannot be auto-sweetspotted, so they cannot be grabbed neither from the back, nor during the attacking portion of recovery attacks. Some moves like Raptor Boost or Bowser Bomb still use this feature, though. Additionally, characters can act out of a ledge grab sooner, and when performing a rolling get-up, other characters cannot grab it until the animation is finished, thus making edge hoping and edgehogging easier.
Hitstun canceling has been removed, causing overall horizontal survivability to be shorter, but giving characters more extensive combo options, which were almost nonexistent in Brawl. Air dodges are no longer usable when tumbling.
Window for teching reverted, making it generally easier to perform.
Items cannot be grabbed during dash attacks or aerials.
Grab aerials cause helplessness if they miss a ledge, but can be used after an air dodge with the shield + attack combination. They still act as tether recoveries, though they won't restore a character's midair jumps if they drop from the ledge.
If an already-struck character gets hit by something else, the new knockback either replaces the old knockback (if the gap between the attacks was 10 frames or less) or has its direction and power combined with the old knockback (after 10 frames). In Brawl, whether to replace the old knockback is based on the relative power of the two attacks, and no merging is performed.
Brawl's random input delay is fixed.
Meteor smash angle reverted, thus implementing the superior, more efficient spikes.
When dash grabbing a foe, forward momentum is completely negated. Unlike in Melee, though, characters with low traction still possess this feature.
Grab released characters will get back their midair jumps.
Pummels reverted to all having the same standarized speed and dealing 3% damage per use, with only a few exceptions.
Grab physics reverted: characters can grab opponents behind them, though they cannot be grabbed by the lower legs or arms.
Characters hit when lying on the floor will bounce shortly and then get up automatically upon landing, or will assume their falling animation if they bounce too high or away from the platform, removing locks, but allowing opponents to perform jab resets.
Though a barely noticeable change, smash attacks can now be charged for 59 frames as opposed to 60, and a fully charged smash deals x1.3671 of the uncharged amount.
Phantom hits now inflict damage equal to half the damage an attack would have done, and while they don't produce any knockback and require a smaller part of the hitbox to connect, they cause the opponent (and not the attacker) to enter hitlag, can be SDI'd, and the real hit can still connect afterwards.
Brawl based changes
Aside from Melee restorations, the following techniques and mechanics from Brawl have also been changed:
Footstool jumping is done with a taunt input.
Tether recoveries now ignore edge-hoggers; characters will still grab the ledge without affecting them, and when pulled up they will perform an automatic jump get-up. This gives characters reliant on this technique a much better and safer recovery, and makes them harder to punish.
Random tripping has been removed. Forced tripping is kept, but only for attacks that always cause it. Tripping can additionally be teched, so punishing a tripped character is more tech chase-orientated.
Meteor canceling revamped: after being struck, all characters must wait for 16 frames before meteor canceling. Attempting to do this earlier results in the character not being able to meteor cancel during the entire hitstun of the attack (except if a jump input isn't used).
The grab release glitch has not been removed: though characters now regain their midair jumps, the new physics now also cause this glitch to disable the ability to air dodge, still leaving characters affected by this glitch dangerously exposed against edgeguarders.
A glide toss can be done in midair with an air dodge. Additionally, air dodges still auto-grab items during the first frames of execution as in Brawl, so that item-based attacks are easier to counter.
Gliding is no longer usable with a jump button: a special move must be used instead to do so.
Super armor has been removed. Standardized knockback resistance system categorizes armor as Light, Medium, or Heavy. Some characters feature color overlays to indicate such armor, with more opaque overlays generally indicating stronger armor. If an attack's knockback is lower than the specified amount of an armor, no knockback is inflicted, but if it is higher, knockback will be regularly inflicted as usual.
Buffering now works differently: the game normally has no buffering, like in Melee, though players can turn on Input Assistance to implement a 3-frame buffer window for helping newer players master advanced techniques, replacing the "Damage Gauge" option. Online matches instead have a different Buffer option that replaces handicaps, from 1 to 30, with these numbers being the respective amount of buffer frames.
Special Brawl's "Curry Mode" is replaced with "Turbo Mode", in which all moves can cancel into any other move or action on hit or on shield. Superspicy Curry is replaced with a "Turbo" item that causes characters to act like in Turbo Mode for a short period.
Other changes and gameplay tweaks
Smash 64's taunt canceling returns.
Stages such as Dream Land, Hyrule Castle and Fountain of Dreams replace stages such as Bridge of Eldin and 75m.
Stock Control added, replacing handicaps. Players can now control the amount of stocks each player starts with before battle, from 1 to 30 stocks for each individual character. A Crew mode has been added in which the game keeps track of stocks retained after battles.
Stage selection menu modified to include built-in stage striking control (Full Set version).
L and R Buttons for the GameCube controllers were tweaked so that the player can input any actions requiring them by just light-pressing them, rather than pressing all the way down, making easier to use techniques such as wavedashing, L-canceling, or even shielding itself (due to Project M's lack of lightshields).
New Melee-like designs for the menu and character selection screens, with altered writing.
The game in general takes less time to load modes, characters and scenes, and things such as Records can be scrolled through quicker.
Brawl mode is now labeled as "Fight!", and all other modes and sections containing "Brawl" are replaced with "Smash" (such as Multi-Man Brawl being named Multi-Man Smash).
Default match type is 4 stock with an 8-minute timer, and Team Attack is turned on by default, similar to the settings of usual competitive Melee matches.
The timer during matches is placed at the top center of the screen rather than at the top right.
Altered camera that behaves similarly to in Melee's Camera Mode, as well as being capable of zooming out indefinitely and rotating around the entire stage, allowing to unrestrictedly take snapshots.
Stage selection screen revamped: stages are now ordered at the bottom in a rectangular shape, with the selected stage being displayed at the top. Stages are now also ordered in Pages 1 and 2, and the top background displays Project M.
Victory screen for VS. battles altered to be entirely black like in Melee.
Independent character icons for Zelda/Sheik and Samus/Zero Suit Samus.
Characters now grunt instantly when hit by a strong attack, as in Melee and 64, while in Brawl they did a second afterwards. There are also medium-damage and high-damage groans as well, with most characters using unused voice samples from the Sound Test. Characters now also use voice samples for sidesteps and air dodges, and variable voices for smash attacks.
Smash Taunts were introduced to more characters, such as Ness and Link, though these are less involved and can be done on any stage.
Characters now emit a spark when wall jumping.
The cast of characters and background at the beginning of the opening movie is slightly altered, and both it and the title screen now display "Super Smash Bros. Project M".
Mewtwo and Roy were added as opponents for All-Star mode.
Training mode now appears as the default Solo mode, and after entering it, the same characters that participated will appear chosen automatically for Group battles.
Home-Run Contest stadium no longer has a protective window, acting like its Melee counterpart. Its online competitive mode has also been added as a co-op mode offline, with records being saved.
No Replay time limit.
Many additional costumes are added for each character, and are shown on the characters profiles as "Colors". There are now also "Special" costumes for some characters, such as Dr. Mario for Mario, Shadow Queen Peach for Peach, and Armored Mewtwo for Mewtwo, some of which get team colors and changed aesthetics.
Due to issues with slow motion, Timers are removed and replaced with ordinary stickers, even for Training mode. Poké Ball Pokémon are also changed slightly: Latios & Latias deal half their usual damage, and Weavile no longer stuns opponents, instead sending them on a weak upwards trajectory. Other items remain unchanged, though, aside from a few Final Smashes.
CPU players have a much more advanced AI, with higher technical skill.
Lo mas IMPORTANTE DE TODO ESTO PARA MI ES SIN DUDA LA VUELTA DEL HITSTUN (TIEMPO QUE ESTAS AGILIPOLLADO SIN PODER HACER NADA ENTRE ATAQUE Y ATAQUE, INCLUSIVE TAMPOCO FINTAS AEREAS COMO EN BRAWL) LO QUE PERMITE QUE LOS COMBOS REALES VUELVAN A SER ALGO EXISTENTE COMO EN MELEE, EL L-CANCEL,QUE PERMITE HACER SHFFLE MAS EFICIENTEMENTE COMO EN MELEE, Y COMO NO LA POSIBILIDAD DE HACER WAVEDASH, YO YA NO SE VIVIR SIN ESTO ULTIMO
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