As the first Kirby game ever, this game doesn't have any copy abilities. The movement is relatively simple compared to most other mainline Kirby games .However, there are still some mechanics that are worth pointing out.
Jumping
Like other Kirby games, jumping is a better option than floating for upward movement unless the latter is required. Unlike some later games in the series, jumping itself doesn't provide a speed boost compared to walking - in other words, bunny hopping doesn't exist in this game.
TAS Spit
Initially been found and used from the TAS runs in the mid-2000s, hence the name. It was found to be RTA-viable as well by Controllerhead around 2018. This glitch will enable kirby to instantly exhale the next object he inhales by quickly pressing either left or right and then down after he exhales something. It's helpful to save minimal times in some boss fights and can save notable time by enabling double hits on King Dedede. When Dedede does his jump attack, Kirby can stand to one side of where he will land and jump, then start moving towards Dedede and inhaling around the time the stars appear. This will cause one star to instantly shoot out and hit Dedede while Kirby stores the other one and can use it to do damage as well. TAS spits also enable doing a double hit with the bombs on the left and middle in the Kracko fight in extra mode (the TAS is even able to do a triple hit by hitting all 3 bombs in 1 cycle and can also do a double hit on Kracko Jr.).
Inhale Cancelling
During the inhale, pressing up instead of letting go of B ends the inhale sooner. This doesn't save time on its own but it's a useful trick for RNG manipulation runs as inhale advances RNG multiple times quickly.
Lag Reduction & Damage Boosting
Like many older games, when too many sprites appear in the same screen, it can create significant lag. Runners try to eliminate certain enemies to keep the game running smoothly, sometimes even by damage boosting. Usually it is equally fast compared to walking. It saves notably more time, however, if there is a door or a warpstar at the end of the boost.