I kinda figured the trailers weren't going to tell you what The Gift is actually about, so I already had high hopes for this movie in the same vain as Gone Girl and, maybe, then some... Definitely will check this movie out hands down!
Yeah I saw this during the pre-movie screenings while I went to see Mad Max, and though within ten seconds "Oh, its gonna be one of these films" and already was predicting everything that would happen. Turns out though that was a wrong expectation, an expectation that many of the critics praising the film had. Seems like we got a real surprise on our hands. I might have to go out and see this on principle of supporting creativity within genres.
The way you describe it, reminds me of The disappearence of Alice Creed. Generic name, generic plot blurb. But when it says on the blurb that it will keep you guessing with plot turns consistently...it really wasn't lying. It felt like a new genre of thriller had been invented. Where it purposefully places the viewer in a constant state of unease, distrust and surprise. Subverting expectations so much that you just stop attempting to find cliches and enjoy what is there. If this movie is even a tiny smidgen bit like that, then I must see it to affirm that this is indeed a brilliant sub-genre of thriller that was not dreamt up in kookie-land.