One of Three

 is an achievement that players can win while playing One Leaves. Players are awarded 150 points when they win it.

Like You'll Be Back, it's a sort of "consolation prize" for losing the game and failing to find the exit. Specifically, it's won by traversing the maze in the sewer and getting trapped. The name means that you are not the "one who leaves", but rather "one of the three" who doesn't make their way out.

External link

 * at Xbox Achievements