Power Levels

Power Levels are a statistic that tells the game how strong a given Droid is. This lets the game be able to determine what a Droid becomes when rerolled, with rerolls giving a different Droid of the same Power Level. However, it also determines what type of Droids can spawn from a Mystery Button, or from killing a Droid with the Random modifier, with this case spawning a Droid with a Power Level equal to the droid with the modifier.

Enemies
(although I've only gotten some of the info either through my time playing this game, or even by viewing old videos and footage, although some if not all are no longer rerollable and only could be in old versions, with the most prominent time of rerolling these droids being the introduction of angelic builder, as its paint ability worked on almost every droid/enemy)