This type of the haunted house is gonna git ya story has been done so often, it's almost impossible to recall how many times I've seen it, here just given a miserable, suburban council house retread.
Assured cinematography & decent performances can't mitigate the terrible decision to make this a total misery-fest, with a cast of entirely unsympathetic characters & a sound track which would drive the most mentally sound to consider topping themselves.
The few horror elements that there were, missed the usual tricks to make the audience jump, this may have been the intention, to avoid overused tropes, but they were genuinely needed here, to help the viewer along. The gateway of the title, does indeed appear & does offer some intrigue, what, why, how etc, but it all comes to nought & we're left with no answers, thanks movie!
The fault here lies with the writer & director, single-mindedly making what they want, regardless of how this won't entertain the audience, you can make a dark, torturous ride, but you have to take the paying customer with you.