I think it's vague on purpose. So it really could mean anything.
For example, the ideas that came to my mind where:
Change by way of physical transformation. Such as a werewolf, where a human turns into another creature.
Change by way of circumstance. Such as a game dealing with a character who experiences a big change in their life, like they've recently moved house or have a new relationship in their life.
(I like RPGs which is why my ideas are both more story based)
I think it's really up to you as the game developer! :)