The premise of the film is interesting, although it doesn't stand to scrutiny if one looks for realism. Without spoiling that idea, it is difficult to review. Somehow, I felt it was telegraphed from the very beginning, as I was thinking "wouldn't it be interesting if that were the case". And it was!
Unfortunately, most of the film is about idiots running from other idiots, with scenes so low budget that they showed the zombie hordes attacking from the back or only the lower parts. That is jarring, especially considering the plethora of zombie films and series that somehow manage to cover makeup or CGI in their budget. The acting was decent, but the direction and editing left much to be desired. From the standpoint of watching pleasure, this film is awful.
Yet, in the end the story comes together and we realize what the film was supposedly about, in the context of today's Sweden and perhaps the world. Is it worth watching the film for this? I would have to say no. And it's sad, because I feel like I would have wanted to like the film and get into its message. It was just too bad.
Bottom line: the basic idea is intriguing and very apropos these days, but the execution was terrible. Even with good production values, though, that idea would have merely have covered an Outer Limits episode time interval, so I don't think the movie had any chance to begin with. Not recommended.