I just ended watching this movie, and I would split it in two parts.
1. From the beginning of the movie to last 20 minutes or so. Awesome, bone chilling, creepy, tense, unexpected, bone chilling again, amazing! Acting is great, music fits perfectly and reminds on old school horror and thriller movies (why there aren't more movies that use violin to create scary atmosphere?!). In one word little masterpiece filmed with rather small budged (congratulations Mr. Wan and crew!). In this part of the movie I decided to write the review, just to prolong the time to go to sleep.
2. Last 20 minutes or so... In here all went down the drain, atmosphere and tensions that were so carefully built were ruined, or at least I felt like that. There are too much scenes and happenings which are unnecessary, and scary factor went away. But never mind, first part compensated it all.
Seems that I don't need to prolong my sleeping time after all... Good night and enjoy one great and scary movie after all!