KA:Rng
While RNG manipulation is RTA-viable for Kirby's Adventure, the number of enemies that advance RNG makes it difficult to sustain a manip for long periods of time. When the game is reset, RNG is set to the same value every time, but it advances every couple of seconds while on the file select screen. There is enough time for players to enter a file before RNG advances as long as they don't dawdle while selecting it. Notable uses of RNG manipulation include manipulating the Waddle Doos in 1-1 for a quick mix and manipulating King Dedede.
1-1 Waddle Doo Manipulation
In order to do this manip, it is recommended to soft-reset the game with A + B + Start + Select after deleting the previous save file (if there was one) in order to ensure that the game can be entered before RNG advances. After soft-resetting, quickly enter the game and enter 1-1. Run to the right, then jump over the first Waddle Doo as it jumps, taking contact damage from it on the way down. Slide off the ledge, passing through the Waddle Dee, and do a small jump once Kirby hits the ground. Turn around and slide as soon as possible while the second Waddle Doo jumps. Do another short jump, then position Kirby and time a large jump so that he can inhale both Waddle Doos on the way down. Keep in mind that the Waddle Doo on the left will stop walking in order to try and attack. This manip can be helpful even for beginners as it is not very difficult to perform and can be used in every category.
King Dedede Manipulation
This RNG manipulation is recommended for beginners since, while somewhat difficult, it is arguably easier than fighting King Dedede without a manip and is much faster. A guide for this manip can be found here. In addition to the instructions in the video, it is important to hold the down button when entering the Dedede fight to prevent ball Kirby from bouncing.