The Diabolical plot twist explained....SPOILERS....

Makes sense to me. Let me try to add a little more?

I imagine that in the original timeline, the mother and her kids move out without a hitch, because the mom was having monetary issues, the offer from the CamSet guy looked good, and there weren't any crazies teleporting back in time. But once CamSet Labs bought the place and started their experiment, they accidentally sent the test subjects to the past at a point BEFORE the house was sold. Which would explain why in this timeline, Jacob gets angry because of what happens to his mother and tries to burn down the lab ... but how did Jacob end up a test subject in the first place? Well I think it is also plausible that Jacob could have ended up a prisoner regardless of what happened to his mother. The movie kept trying to show that he had a short temper and was prone to violent behavior, just like his father. The cause of his being locked up could have been different with each alternative timeline.

The part that I still can't quite figure out, is why he and his sister couldn't leave the house, but the mother could. The best I've got so far is that Jacob's future self grabbed / touched both his child self and his sister. Future Jacob and his mother didn't touch until the very end. I suppose that once you are touched by someone from the wrong timeline, you begin to cease to exist once you cross the threshold of the portal? Which may explain what was happening to the CamSet guy who was trying to leave the house after getting attacked by future Jacob? What do you think about that?

Now, CamSet are obviously unaware they are sending these guys to the past. As far as the prisoners are concerned they are just showing up at some random house not knowing where they are, totally messed up, until Jacob turns up and recognises where he is.

They have accidently discovered time travel.

When the mother goes back with him they must've realised why they haven't been so successful and fixed her up and sent her back.

This then messes up her brain which in turn angers Jacob and his anger gets the better of him again making him try to burn down the labs, which in turn causes him to be locked up and subjected to all the experiments. Which then leads to him being used in the teleporation experiment, which leads to him time travelling instead. Ain't time travel a bitch!

Let me know what you think.

I agree that CamSet is working on teleportation, and the scientists don't know about the time travel because the human guinea pigs they use get so messed up they can't tell anyone. so when Madison (mom)returns with future-Jacob, she can tell them and end the cycle. but since she goes back all fixed up, I don't think Jacob has reason to bomb CamSet for revenge, it's the start of a new timeline cycle - like when future-Jacob cuts boy-Jacob's cheek, the cut then appears on future-Jacob's cheek.

I really, really wish this movie had spent more time after the "twist." like, first half on the ghostly dudes, second half on the time travel. it felt ridiculously rushed!

That offers up great explanations, but what I am still confused by is why there were three versions of the entity or whatever you want to call it. The one in the washer/dryer whatever did seem to resemble the fake realtor guy in the way he crawled (which someone mentioned somewhere on the board) but if it was him why did he teleport/time travel, or was it just because he was touched? Or maybe it was all Jacob in various times he teleported back. I did notice though until the end he wasn't really hurting anyone they started attacking him.

Also I don't understand why Jacob would try to blow up the place as his mother did come back (not sure what you mean by her brain was messed up), unless it was dealing with multiple alternate timelines. Also I wonder did Jacob not recognize it was his future self or just couldn't control his anger to understand that by getting revenge was what caused it to happen.

Also I do appreciate that that movie makes you think; I'm just curious how many people will make it far enough into the film for the twist. The script was ambitious, but in my opinion never quite made it there, because it didn't get interesting until at least 2/3 into the film. I didn't find any of it scary or even have "jump scares," though maybe some people did. I don't know I tend to get scared at films easy but not here.

That's alot more coherent than the film!

I didn't understand why he attacked his mum though.