Gameplay speed

Gameplay speed is a feature in all Super Smash Bros. games that increases or decreases the framerate (and subsequently speed) of gameplay. Each iteration of Special Smash has featured a slow and fast mode. There is also an option in Training Mode that allows the player to increase or decrease the speed of the gameplay to one of several presets.

In Super Smash Bros. and Melee, when gameplay is slowed down, the game runs at a visibly slower framerate, and even the Training Mode menu is slowed down. When playing in fast motion, some visual frames are skipped over during gameplay, and menu interactions are also sped up. However, Brawl introduced interpolated animations for 1/2x and 1/4x speed, giving the impression of 60fps gameplay, while calculations are still carried out at the slower framerate. Smash 4 added this feature to 2/3x speed as well, which was carried over into Ultimate.

Other causes of slow motion
In addition to the Special Smash and Training Mode settings, future games would also introduce other sources of slow motion, while fast motion remains exclusive to those modes. These include:


 * Dialga's Roar of Time – When Dialga uses its Roar of Time attack on the Spear Pillar stage, the speed of gameplay will be reduced to 1/2x speed.
 * During the activation of some Final Smashes. Notably, most final smashes utilize Slowdown, but a handful of final smashes also use slow motion.
 * KOs in stamina mode – When a fighter is KO'd in stamina mode, slow motion is activated for about a second. In Super Smash Bros. Ultimate, this only occurs when the fighter's last stock is lost.
 * Special Zoom – The game speed is greatly reduced while Special Zoom is in effect.
 * Several explosive items in Ultimate, including Bomber, Fake Smash Ball and Motion-Sensor Bomb. Several other explosives freeze the victim briefly, but this appears to be a different effect.
 * The Daybreak item, shortly before firing.
 * The Dragoon item, while firing.
 * 's Kamikazee, shortly before he self-destructs.
 * When clearing various battles, such as in Classic Mode or against false characters in The Subspace Emissary, during the victory zoom in.

Outside of Training Mode and Special Smash, fast motion is rarely used, however certain Events in Melee use fast motion.

Issues/glitches
With the addition of the interpolated animations in Brawl, several issues were created. Most notably, inputs on the C-stick tend not to register correctly, which appears to be a consequence of the inputs made by the C-stick being made for only a single frame, and input buffering not activating when inputs are made in interpolated frames. This issue was fixed in Smash 4, but some other issues persisted, and new ones were created:


 * Certain transformation Final Smashes will not have their durations extended by slow motion, effectively making them last for a shorter amount of gameplay time. This also applies for Hero's Command Selection menu.
 * 's smash attacks can hit 2 times per shot instead of 1, doubling their maximum damage output. This issue persists in Ultimate.
 * and 's grabs in Ultimate have altered ranges when the gameplay speed is changed, with the former having reduced range, and the latter having increased range, especially vertically.
 * Tethers when used in the air behave differently, altering their range and how the user's movement affects them. Additionally, 's Fishing Rod physics are much more erratic, making the bobber harder to control.
 * 's Winged Pikmin run out of energy very quickly, drastically reducing how far he can recover with them. This issue persists in Ultimate. Oddly, similar up specials like Robo Burner and Balloon Trip are not affected in this way.

Oddly, none of these issues appear to apply with slowdown, which has its own set of issues.