Lights Out - a TV horror movie

Watched this little US horror film tonight.  My rule of thumb for films is that longer than 150 minutes is too long, but shorter than 80 minutes is too short.  When you get down to something that's fewer than 80 minutes, I start to wonder why this is a feature length film at all and not some sort of made for TV movie.  Well Lights Out is a good case study in this.  It's 77 minutes long, and though modern film technology allows it to look like a proper film, the story progression, direction and acting occasionally make you wonder if this should be on the SciFi channel.

Lights Out starts with a suitably horror opening.  We are inside a warehouse with the night shift.  As they turn the lights out the silhouette of a woman appears in the distance.  The worker flicks the light on and it's gone.  The light is flicked on and off several times, with the silhouette appearing each time the lights go out, until the light is turned off one last time and THE SILHOUETTE IS RIGHT IN FRONT OF US!  A nice opening.

What should be the prelude to a mystery ready to unfold soon turns an X-Files episode with a family secret, a medical experiment gone wrong and a nice moral ending.  The film doesn't give enough space to the plot to allow the mystery to linger and get under your skin before it becomes normalised and our heroine finds a box of exposition that explains everything (this literally happens).  In a TV show you have to get things moving quickly, in a film - not so much.  The film's creators didn't seem to realise that they had 90 minutes to play with, and that they didn't have to immediately reveal who or what the dark silhouette is.  Horror fans are happy to enjoy an opening act of gore and jumpiness before we get into the whys and hows.  Also horror films need to abide by their own set of rules.  Is silhouette-girl actually gone when the lights are on, or is she just invisible?  It she tied to the mother or not?  It isn't really clear what the rules of engagement are here, before everything comes to a conclusion that could have happened years ago in the film's timeline, then everyone lives happily ever after.  Have these people never seen Carrie?  They always come back!  If they don't come back then your average horror film fan is going to feel let down - as I did.

Bit of a disappointment to be honest.  Only watch if you are a genre fan.