Rule Number One

The story was well-written especially for a topic that has essentially been "beaten" to death by HK movie makers in the 90s. The plot is intelligent but not too clever. There's no mystery about things in the story, nothing that hasn't been seen before.

The twist in the end wasn't unexpected, but I found it a tat bit too short and should have been made a little bit clearer.

The horror factor of the movie, to me at least, was the use of sudden loud noise/music that is so common these days among this genre.

Well, for one who isn't into horror genre, I'll tell you to go watch this one. Don't expect the unexpected though.