While the acting is decent, the lighting of too many scenes is poorly done and too dark. This makes watching these scenes distracting. For a film that focuses on one house you would think the director would have spent plenty of time showing you the whole house and the surrounding neighborhood. Instead you frustratingly see the same inside-outside shots as if the front porch, the master bedroom and the main foyer is all that exists. This does not add to the suspense it just makes it annoying as you cannot judge how far she really is from anything else.
Apparently the director and writer have never lived in the suburbs as they attempted to paint them as some sort of caricature of what they are really like. In the United States I have lived my whole life in the suburbs, in six different homes, in three different states and not one was remotely like the abandoned ghost town they tried to create in this movie. I kept laughing as I watched them literally try to make living in the suburbs some sort of "scary" ordeal, please.
Only someone who insanely hates the suburbs and refers to the homes as "McMansions" would like this movie. Those who hate the suburbs usually have never lived there and/or are environmentalists who falsely believe suburbia to be some sort of problem. Not realizing those who move there choose to of their own free will and do so for legitimate reasons. In Ireland I suspect the recent flight to the suburbs is a new development (no pun intended) as the U.S. went through this change after WWII. For those who choose to live there, the suburbs are a higher quality of life compared to urban living.
As for the plot it is monotonous (over two hours) with the ending not really resolving anything. The whole time you have the naive main character (Molly) making stupid mistake after stupid mistake while ridiculously trusting a worthless alarm and anyone who gives her advice. After the first break in, I would have gotten an alarm with cameras, more secure doors, a dog and a gun (Thank you second amendment!) not wait around to be a victim like Molly. Do yourself a favor and watch something else.