Spoilers might walk out of the movie.
I took no pleasure in watching this. I’m letting you know right now, because although there is an audience for this film, it was very divisive. For me, it became uncomfortable just past a third of the movie in. I am reviewing it because as grating as the experience of watching is, it has kept me thinking about it for a while. The movie has a message but perhaps I needed some sugar coating to swallow the bitter pill that is its content. I’m going to include a warning for disturbing content below.
Koko-Di Koko-Da was written and directed Johannes Nyholm. Tobias (Peter Belli) and Elin (Leif Edlund) go on a trip with their young daughter. They give her a gift, a music box. After Elin suffers a severe case of food poisoning, their daughter collapses of unknown causes. Years go by and we are reacquainted with the young couple driving in the woods. Elin pleads Tobias to find an inn to spend the night. Tobias drives them deeper into the forest while insisting he can set up a tent anywhere he pleases. Their relationship has obviously deteriorated.
In the early hours, Elin needs to relieve herself. Tobias tells her to do it somewhere outside and away from the tent. Three characters representing the drawings on the music box show up, the ringleader singing the children’s tune from the title, a girl with a brown dog on a leash and a brutish man carrying a dead white dog. What happens next is disturbing to watch. The dog is sic on Elin. We don’t see the actual biting, but we hear the dog snarling and Elin screaming. Meanwhile, Tobias hides in the tent fearing for his life until they also get to him.
Once the vicious and violent episode ends, the cycle repeats. First, almost or similar to the one before and after that, when it repeats again it seems Tobias recalls the previous times and tries to save himself. Yes, himself only. He doesn’t try to include Elin until some loops have passed, which gives us ample times to hear Elin been mauled by a dog. I understand they are going through a time of painful and unbelievable grief. I don’t really need a gruesome mauling to somehow feel empathic. I felt disgusted already at Tobias not helping his wife. Thankfully on a later loop it’s Elin who recalls the episode and tries to get herself away.
There are these illustrations with bunnies capturing a rooster that make it clear to us less enlightened souls (read: sarcasm) that the cycle of grief is perpetuated when you keep it all in. I could see the message of grief. I’m not sure why grief over a personal loss needed to be illustrated with being attacked by a dog, shot in the genitals or crushed by a giant. There is no parallel. I can empathize with grief, having lost a loved one myself. I cannot empathize with being mauled, shot or needing to run away of a trio of killers. Comparing suffering is a pointless exercise so I really hope there was a different interpretation here. Otherwise, I fail to see the point in holding your audience hostage.
Not recommended. Yes, there is an audience that will decipher it. I doubt they’d enjoy the experience of watching it, much less recommend it themselves. I found it frustrating and uncomfortable just to witness the implied animal attack on a person, much less watch it several times. I believe movies are made for audiences. That doesn’t mean they have to be dumbed down, but if you are putting symbology in your movie please make it palatable enough that they will sit through it. It might have an audience that can sit through it. I just would rather save you the suffering.
That will do for now.
Never Think Impossible 
***Spoiler Alert***
I cannot argue with the facts you present, but I disagree with the final impression. The various iterations the husband goes through show a very realistic “learning curve”, and as for his cowardice, I suspect I myself wouldn’t be able to muster the courage to take on three psychos (one armed with a pistol, one armed with his sheer bulk) and their attack dog when I possessed what was merely a glorified butter knife.
There is nastiness in the movie, and it is difficult, but for me it was not so difficult as to turn me away (but I’ve had considerable experience watching movies that were far more unsettling). The resolution, when the wife has her vision — for vision it is, not a loop, as we see her awakening in a different season, having aged at least a decade compared to her “real life” self — was more than enough pay off for me, as the couple drove off from the danger and found their happiness with each-other.
The cruelty found in “Koko-di, Koko-da” was apt for two related reasons. First, it showed the unrelenting pain that unresolved grief can inflict, and second, in so doing show the importance of clinging to those whom you love when such grief afflicts you. We saw a build-up of three years of torment made manifest in the forty minute conclusion of the film. I couldn’t expect anything kinder being remotely believable.