Finally caught up with this. Well, well--it's surprisingly good, up until the moment when Aubrey's prosthetics look too Frankensteinese to suspend disbelief, and Orestes Ojeda gets into bed to strangle her. But it recovers with Castillo's light-and-sound climax, and Bagatsing delivering an emotional voiceover speech.
This is one of Ad. Castillo's better efforts, I think (it hain't as inspired as Lihim ni Madonna, tho), and a better showcase of ole fashioned non-CGI filmmaking than Matti's Pa Siyam. I'd even say it improves on its source material (not that I'm a big fan of The Exorcist).
Now if Ad. Castillo would only deign to do a superhero film. Supermanhid, anyone?