Christopher Nolan-lite is definitely becoming a sort of sub-genre, partway between sci-fi and horror, more of a niggly brain itch than an actual brain tease.
In Parallel a group of millennial app developers discover a portal to the multiverse in a hidden part of the home they share. The concept is almost immediately understated to death when they discover that their limbs disappear into a full body mirror: "That's weird".
And then I had a premonition that they were about to quote Arthur C. Clarke, which they duly did. And that very selfsameness between high level magic and tech is part of the problem with Parallel, because in terms of elucidation (and philosophical exploration) we never progress much beyond that initial note of humdrum strangeness.
Our four friends have soon figured out that through this particular looking glass lies a multitude of 'alts' — parallel worlds where time runs slightly slower, which conveniently allows them to overcome their immediate predicament, an impossible deadline.
Thereafter they turn to other ways to develop themselves personally and professionally, in the main by ransacking the intellectual resources of these mirror worlds.
Although many of the more intriguing possibilities are left unexplored (or at least evaporate almost in the very moment they are revealed) by the end, the action has donned a cloak of confusion worthy of a more stimulating screenplay.