Over two-thirds of the runtime is wasted on uneventful, flat dialogue. None of the actors connect with one another in deep, meaningful ways. The director likes little details in the background to build up the suspense, which is admirable. The number "five" is important but, given the satanic vibes, six would've been more appropriate.
There needs to be a clear and present sense of danger (to the audience) in a story like this. Repeated false jump scares and the "figure standing/watching in the shadows" cliche just don't cut it. The production unintentionally looks like an amateur home movie at times. Some scenes make you question if the writer had any second opinion at all. A professional critic implied they expected the group to do a head count throughout, to see who's still with them, or alive. Leaning on that would've forced the pacing to pick up far sooner, and drastically changed the story for the better.
What we got feels like it was concocted by a Mormon. If you drink or smoke, then you should just die; you're a monster on the inside and totally irredeemable. This story not only fails to explore the causes, dynamics, or potential solutions to substance abuse or suicide, but it fails to even create worthwhile characters or a decently-paced thriller.
Captain Hindsight (What I would've done):
Make the protagonist care about others, giving him good reason to stay/live. The absent brother is a hopeless degenerate. Have the main guy connect via history or interests to a few, and even inspire them to turn their lives around. Life isn't black and white, SHOW how some in the group are truly despicable, while others are just caught up in a hurtful world. As the rest get picked off, this plays with the theme of urgency in halting abuse. The first few deaths might look like accidents, the rest must serve to build suspense - becoming more obviously horrifying in a crescendo. The Predator-style gimmick of "not killing IF" must be toyed with, teased until the audience really is unsure of how this will end. E.g., one guy just really needs one more drink to himself after a close someone dies, and thus doesn't make it. In the end, a few make it out, eager to start anew - but did the change happen before, or after? The protagonist realizes his brother is worth fighting for. There is so much to work with here, it's a shame how it turned out.