Multiple endings
Also said as Branching endings, True ending
The story can finish in more than one way, depending on what the player did. The choice may be made in the final minute or built up over the whole game.
It rewards replaying and gives choices a place to land. The cost: most players see one ending, so the rest of the work is hidden, and a last-minute choice lets someone reload and see them all in a minute.
Say it
“Do not make the ending a final menu. Add up three flags from across the game and pick one of four endings from that, so nobody can reach another ending by reloading in the last room.”
Where you’ve seen it
Nier: Automata has 26 endings named A to Z: five that carry the story, and the rest mostly jokes and sudden deaths. Undertale's ending depends on how many monsters you killed over the whole game.
Not to be confused with new game plus
Multiple endings are different ways for the story to finish. New Game Plus is a way to start over and keep things. Some games use the second to reach the first.