Wavedashes
A wavedash is a commonly used technique in Celeste that allows the player to perform a small, but long jump, while also regaining a dash. It's introduced in Farewell, right after passing the heart gate, and it's frequently required in order to pass a lot of rooms in the chapter.
Functionality
Other variants
Bubble Wavedashes
Bubbles allow players to stall in mid-air for a short time, and if they're at a specific height, Madeline will be able to perform a wavedash if the player aims in a down-diagonal position and jumps off of the ground before the dash momentum wears off. Although the vanilla game never requires you to do this trick, it's often used by speedrunners or in custom maps, where they're often used as setups for consistent wavedashes.
Extended hyper
In short, extended hypers are a grounded variant of a wavedash. While the game teaches you to do wavedashes from a specific height, it's not necessarily required, as long as you jump when Madeline's hair flashes white. The effect is the same as with a regular wavedash, but it's an alternate way to perform for people who don't feel comfortable doing it from air. Its only disadvantage is that it's much more difficult, if not impossible to perform it from small platforms.
Reverse wavedash/extended hyper
While performing a wavedash or extended hyper, a player can quickly switch directions before jumping, to do a backwards jump. This move is useful for places, where the player might not have enough room to do a normal wavedash.
Extended demohyper
A type of extended hyper that's performed by jumping after doing a demo dash from ground, usually used with a demo bind. A demohyper behaves nearly identically to its normal variant, except for it giving you slightly more distance due to the player doing a straight crouched dash, instead of a diagonal, as well as it allowing players to do a demohyper from mid-air. Due to the technical difference, it's usually not recommended to use demohypers from ground, but they're often used by speedrunners to perform the move from mid-air.
