Though some audience are happy with that, praising how smart it is of movie makers to leave the ending open so that viewers will participate in the story's plot, and so that the intellectuals are free to form a thousand plot possibilities... I am not one of these viewers.
Yes, I am the type of customer who orders at a fast food hungry and expects to eat a whole cheeseburger, with fries and drink (if I ordered that exact list)... nothing less! I don't expect to be served a half-eaten burger or be served a burger missing its lettuce, onion and tomato just because the crew doesn't feel like going to the pantry and slicing pieces of the hamburger components and then be expected to understand the staff just because "matalino naman ako" and I can adjust.
In the same way, I don't expect to watch a movie and invest my attention and feelings on it, only for it to end abruptly just because. It feels like being asked to play a game with someone, and in the middle of the game, my opponent would suddenly quit out of the game and suddenly shout "Ayawan na! Ayawan na!" just because.
I feel it lacks manners... like I am deprived of something that's rightfully mine. (At this case, of a proper ending to a movie.)
So yes, this is a note to movie and story makers that when you create a movie or a story, please deliver and finish it with no excuses. Thank you.