We heard the players and viewers. The "open to interpretation" ending was not very loved and left a lot to be desired.
The game didn't have any conclusion/closure and after thinking about it, we felt it comes across as incomplete.
So, the game has a proper ending now (a twist end actually) and reveals the killer to be who we've had in mind while making this game.
We know some players might want to replay the game to see this ending (or to just get all the achievements). Since the game is cutscene heavy, we'll be introducing a way to skip cutscenes next.