They Came Back

After I realized this movie is not a horror or a trash one, just because it has zombies in its plot I thought it has a great creative mind behind the story; however, when the movie ended I felt there was something missing in the story. The movie does not care much about explaining its core issue that is about the coming of the dead people themselves. Why did they return to live if all they want is to go to the tunnels? It does not say where the tunnels will lead them. To heaven or to hell? to the Elygian fields? to Mars? or to some new dimension? I would not bother if the movie was longer just to explain this part carefully. If so,the movie would be brilliant. Unfortunately it is not a brilliant movie. It is only good to make us think about the crazy hypothesis that the movie is talking about, which is, at least, interesting. My note is to say that according to my own interpretations, the movie never tries to sound funny as some other critics say, but tragic and hypothetical. People are never prepared to welcome their dead relatives with eager if they knock at their door after some years of "absence", even if you love them so much.