I recently painted my entire house, I spent a lot of time watching paint dry. That was much more fun than this. Slow. Really slow. Tediously slow. Little script. Not much happening. Dreadful acting. I've had root canal treatment without anaesthetic where the time passed more quickly. Good for insomniacs, but not for anybody else.
I have to say that the setting for this film was in the darkest, most dismal and ugly home imaginable. Long dark corridors, equally dark rooms, most with dark doors with an almost invisible chinese-style pattern on. These doors hid kitchen cupboards and room entrances, which were so narrow they were barely wide enough for a person to walk through, where the doors themselves were almost invisible. The rest was in wide open glassed areas that seemed to stretch in columns against an unidentified hillside with no signs of human habitation. Despite this, the film is not really horror, but science-fiction.
There was no explanation as to what had happened to the girl's arm nor to her mother, and no explanation about whether her dog was speaking telepathically or carrying the gadget which contained her mother which spoke to her. What time was it set in and where did the cube come from?
Even if you get some gist of time-travel it takes a long time of wading through the slow chapters of the film (each labelled), before you have any guesses as to what is going on. There is also some extreme violence which is over-the-top even though the reason for it is explained - the Trojan horse idea, get an injured girl to be taken into the house to enable a crime to take place, but the 'fake' set-up violence is totally over-done.
Another irritation is that a very large amount of the film is acted out long-distance. You feel you are in a theatre in the rearmost seats trying to work out what is going on on-stage, as it is so far away it is difficult to make out which characters you are watching. I see no point in this as it is less 'arty' and more frustrating than anything.
Next the acting. I don't like subtitles in films as they detract from the film itself (unless it is a foreign-language film or American, where I need the subtitles because their diction is so bad), but in this one they spoke so quietly, in mostly English accents, though one might have been Australian, that it was really hard to make out what they said, each of us going 'what?' at many points in the film. But in a really rare situation, there were no subtitles available! In this film you most certainly need subtitles. The actual acting varied up and down througout from very poor or totally over-the-top histrionic.
Many of the actions were bizarre and a day later we are still trying to work out why they were there. For example on bringing an injured girl into the house why was she immediately submerged in a water bath that seemed to be at the end of a corridor? Why was a bath of water even there when you might fall into it at any point?
There was no clear ending, just an intimation of what had probably occurred and was going to occur and you were left wondering, right through the credits as it focussed on the cube, we were expecting something to happen after the credits rolled as so often does in films now
(and this is a 2017 film) but it didn't, the cube stayed the cube and that was it.
So in all I would say that unless you really want to punish yourself for some masochistic reason I would say give this odd film a miss.