De Palma complained about the difficult production conditions: "I had a lot of problems in financing. I never experienced such a horrible movie set. A large part of our team has not even been paid yet by the Danish producers. The film is finished and ready to go out, but I have no idea what its future will hold, it is currently in the hands of the producers. This was my first experience in Denmark and most likely my last." [2018]
According to an article from Aug. 2017, the film had "a budget of NOK 50 million [about $6 mill.], of which the Copenhagen Film Fund has contributed two million to get eight or nine [shooting] days to Copenhagen". De Palma later complained in interviews that the film was "underfunded" and shooting it was a "horrible experience" because of many delays, but it could be completed and the final result was "very good".
There never was a 'longer' version of this movie according to the assistant editor. Director Brian De Palma confirmed in June 2019, that the released version is his cut: "It was not recut. I was not involved in the ADR [Additional Dialog Replacement], the musical recording sessions, the final mix or the color timing of the final print."
The film takes place in Denmark, the Netherlands, Belgium and Spain.
The Hitchcockian score is by Italian composer Pino Donaggio, his 9th collaboration with Brian De Palma, having first scored the director's Carrie (1976).