If you've seen a couple of horror movies, nothing much will surprise you in this. "Twists" are not really there - not even in the ending. I'm surprised some would call it a twist or "reveal". It is actually pretty obvious, I didn't for a moment think anything else was going on.
So this is decent overall, with shock effects and a story that is easy to follow. Based on something real - there are quite a few things we can't explain that happen when we sleep. Which can make the mind make up stuff quite easily ... or is it not made up? Well whatever you may think of such fantasy and horror, will determine if you're entertained or not