For a film to work you have to offer your audience some form of entertainment. If story or plot isn't the priority, then you have to deliver pretty great dialogue. If you can't deliver great dialogue then you have to put on show high quality acting. This film has none of those three important components.
If you can't offer those essential three, then you better offer some sort of thrill or visual feast. This is clearly not that type of film either. So what you left with is basically a cheaply shot, amateurish play with no substance. It's simply poor writing.
Example, rather than show the woman becoming more dysfunctional we get to hear it through a friend. And not even in a type of revealing story way but in a 'I think she needs to see a doctor something's going on' way. It's exposition. The number one worst rule of screenwriting. I question the motive of critics and wonder which film they've seen.
Long takes can work wonderfully too but here they offer no artistic reasoning. It wants to be high art. It wants to be the indie films of the 90s but it's really very shallow.
The only redeeming quality is the lead actress. She pulls it off but only just. The rest reveal their shortcomings from the opening moments. There are far better low-budget films around that haven't received the type of publicity this one has. God knows why.