In Super Smash Bros. 4 and Super Smash Bros. Ultimate, an amiibo’s Level refers to its growth progression. When an amiibo is scanned into a Super Smash Bros. game for the first time, it will start at Level 1. At Level 1, amiibo generally stand still save for a small number of neutral attacks. After being defeated by its trainer, it will become smarter as its level increases. Its level can increase to a maximum value of 50.
In Super Smash Bros. 4
From Levels 1-49, an amiibo learns most if its trainer defeats it in battle. At Level 50, an amiibo will learn more if it is defeated by an opponent. This, however, became a double-edged sword: if an amiibo lost to a Corruptive opponent, its play style would be immediately ruined; the character would then require extensive training to correct its newly-acquired bad habits.
Compared to a regular player or CPU, Level 50 amiibo have significantly increased Attack and Defense. They are boosted by 50%, which casual trainers note puts them at an unfair advantage against humans. For this reason, amiibo in Smash 4 are not good sparring partners, as they have an inherent stat advantage that cannot be reversed.
With the help of Amiibo Powersaves, it was possible to change a Level 50 amiibo back to Level 1 without resetting it. The amiibo would still act the same as it did at Level 50, except with decreased power and defense. Leveling it to 50 once again allowed it to learn new habits more easily.
In Super Smash Bros. Ultimate
In Super Smash Bros. Ultimate, an amiibo’s level works essentially the same way it did in Smash 4 with a few exceptions. In addition to leveling up an amiibo through battle, it can also level up by inheriting Spirits. Doing so also changes their style. Without the aid of Spirits, an amiibo’s style can be changed in battle; however, most amiibo do not develop a style other than Normal until Level 35.
Unlike in Smash 4, manually changing a Level 50 amiibo to Level 1 does not change how they learn new tactics. As a result, it is now considered to be a waste of time compared to its functionality in Smash 4.