Interstellar is a truly astonishing piece of film-making. Let's get that out the way. It is far from perfect but undeniably impressive visually and one of the most ambitious stories told on screen in recent years.
Nolan does not treat us like idiots as some of his peers might (I'm looking at you Michael Bay), this much we know from his back catalogue. Inception is a truly original film and The Prestige is so deviously clever it demands to be seen again. Interstellar goes beyond keeping us on our toes however, it is a difficult film. The theory of wormholes, time dilation and relativity are not easily digested, so Interstellar demands some chewing. That is not to say it is not worth the journey, many will find it being one of their films of the year. Some however, will find it too much, they will take umbrage with the sometimes wooden dialogue and painful running time. Hitchcock once said that a film's length should be directly related to how long one can go without needing the bathroom and it is safe to say he would have needed a colostomy bag for this one.
I for one was enthralled from the slow-burn start all the way through the 169 minutes to the excellent ending. To enjoy this film you need to be open and get on board with the science, otherwise you will get distracted by some of plot-holes or lack of logic. Science fiction is not meant to be be entirely realistic, it is pure escapism and you will get more from the movie if you just enjoy the story for what it is.
In recent years it has been packaged (with notable exceptions) as off-planet action movies on steroids with varying results. There have been good films like Guardians of the Galaxy and the first Star Trek reboot, but a ton of schlock that has diluted the genre. Sci-fi was forged by Kubrick and Tarkovsky and is a thoughtful and exploratory category of films. Both these legendary director's influence can be felt in Interstellarand the film is all the better for it.
Nolan has made a film that harks back to the origins of the genre and that is both brave and risky. It is a splendid movie, but it is not for everybody.