The Ritual is tough for me to think of much to say about. Not that it's bad or dull or mediocre; in fact, it's a well-made and interesting movie. There's just very little worthy of saying or explaining to you that wouldn't ruin the movie.
The film starts off with some British cunts drinking and discussing their next boys' outing. Where in the world will they go to party? One friend suggests a Scandinavian hike getaway. The idea is mostly pooh-poohed. One of the friends, Luke, insists on stopping to pick up some liquor, because he's still trying to party like they're young. Unfortunately some very stereotypical junkies are holding up the store. The would-be hiker is robbed while Luke hides and watches. After refusing to give up his wedding ring, Luke's friend is killed while he silently watches from safety, unable to bring himself to intervene.
Cut to the remaining four cunts on a hike, honoring their fallen friend's memory. They mostly argue and bicker and make you wonder why they were friends in college in the first place. There's still an underlying tone that they blame Luke for standing idly by. They hike trails in the Swedish countryside until one of them hurts his knee and they decide to leave the trail and try to take a direct shortcut through a forest to get to civilization more quickly. In the woods, things go poorly.
Now, I can tell by reading a synopsis of the novel it's based on (something I never would have imagined from the trailers or even watching the film) that the screenwriter drastically improved what was on the page. Some of it seems a little silly compared to the handling the film gives it. So it absolutely deserves credit for removing all the hokeyness from the film and keeping it grounded. In addition, it sound like the plot involving the murdered friend and Luke's complicity in doing nothing to stop it is invented whole cloth for the film. Which is genius. If the arguments between the friends were about the fact that Luke is the only one who was never a success and the others have failing relationships and unfulfilling lives, it wouldn't have worked. Pretty much the entire third act is completely modified. So, kudos to the screenwriter, Joe Barton. It sounds like you truly turned this story into something more by giving it some depth.
The actors do a fairly good job of mostly playing characters I didn't like or care about. It's probably to the benefit of the film that I had no use for any of these pricks, so I was fairly sympathetic toward Luke by the end despite starting off with his cowardice and lack of any redeeming traits. He's the only one that seems to take their situation seriously, so the audience automatically sides with him. It's not an acting-heavy film, but everyone pulls their weight and fits their role well.
The visuals are exceptionally strong. For what it is, the film looks excellent. In many ways, the film reminds me of The Descent and David Bruckner has the same sort of ability to create a crisp visual style as Neil Marshall. Not to mention that the plot has strong Descent similarities, with a group of friends going on a remote vacation where the environment is more dangerous than expected and they're whittled down by supernatural enemies, leading me to feel like it was a bit of a rip-off when I initially saw trailers. But this film, somehow, feels more rich and balanced than The Descent and the color palette and mood of the final act and the dream sequences definitely make it worthwhile, especially since you think early on that the movie is mostly going to imply the horror instead of showing it. Not so. (I'll go so far as to say that I think it's a better movie than The Descent, as much I enjoyed that movie in the past. The pieces of this just fit together better and the pacing feels just right, comparatively.)
It may have taken me a long time to finally get around to this and, while I wouldn't say it's groundbreaking or features anything totally unexpected or life-changing, I'd been more inclined to recommend this to others than many better movies I've watched recently. There's something sold and intriguing about it and they definitely wrung everything out of the film that they possibly could have. So, if you too have been putting it off, go ahead and watch it with my recommendation.