The new film where Lars von Trier is claimed as one of co-directors (the other is Iorgen Leth) is a semi-documentary one that in my opinion should not be treated too seriously. I think it's just a joke (and sort of rest for Lars between two films of his ambitious "American thrilogy"). Although, of course, every joke can contain interesting ideas.
I believe that von Trier does love cinema, in spite of some of his controversial expressions (that are nothing but epatage) and strange anti-cinema project Dogme-95. He really can enjoy this form of art. And "Five obstructions" is a great fun for cinefiles, full of daring experiments and irony that can entertain you.
It's unjust to say that von Trier is an author of this movie. He has only inspired talented documentary filmmaker Iorgen Leth to create five short documentaries (except for the last one) that are the main constituents of the film. But to inspire somebody is also a specific ability, isn't it?
What was von Trier's idea? He said that restrictions could be a great impetus for a creator (e.g. who knows whether all Tarkovsky's feature films were masterpieces if he hadn't been oppressed by Soviet authorities). It was a ground idea for the movie.
Being a great admirer of Leth's early documentary "The Perfect Human", von Trier suggested him to play an interesting game: Leth shoud remake "The perfect human" five times following every time a specific rule invented by Lars. So, the film consists of these five "obstructed" remakes and von Trier's reasoning about them. Some constraints are really excited, some are rather strange (e.g. extremely short shots), but every time we get marvellous short movie.
Anyway, all of them reveal great opportunities of cinema: one story can be told in so many ways and every way has its own charme!
Great Russian writer Vladimir Nabokov once said that every real Artist, while creating, impose some inner restrictions to himself, and a true piece of art is a result of overcoming of such "obstacles". I'd prefer not to consider "Five obstructions" as such a researching of deep origins of art, but this film, created by people who does understand cinema and can appreciate it, is a pure delight for real cinema lover! Undoubtedly worth seeing!