Could've been better, some Spoilers within

The first minute had me hooked and interested. The first story at the 911 call center was great!

But all the stories afterward were not as good, and we are offered no real answers to the portals. Personally I think they are demons. Because they keep offering deals with people to get them to do bad things or compromise their convictions. They make people question reality and say things like "nothing is real", "happiness is all that really matters", its stuff evil beings would whisper in your ear to make you a lesser person and think negatively.

The take I get from this movie is "Dont make deals with demons, and dont let anyone make you go against your gut instincts".