There is a certain snobbery with films that require more than a small amount of attention – an opinion that if you even ask about a small detail that you missed that you should then go watch Transformers and leave real films to the grownups. It is unpleasant superiority and it is mostly undeserved because to be honest this is a hard film to follow and it does demand attention. Those wishing to insult me via private message can do so, but I did struggle several times to understand how things fitted together and what relevance certain scenes had. This didn't limit my enjoyment of the film though and mostly I still followed the broad stroke of the plot, even if some bits of it did lose me.

I've not read the tome of a book or seen the BBC mini-series, so I can't comment how well it compresses down to this two-hour film, but for me it did at times seem to be cramming a lot into a small time and occasionally it felt like it was unnecessarily convoluted or confusing. If you stay with it as best you can, it is intriguing and rather dramatic considering that much of the film is people talking to one another as opposed to chases and gun fights. The success of this is mostly down to the atmosphere and tone created by director Alfredson, because there is a constant tension to the film – cold perhaps, but very tense at times, certainly not bored even if it can look that way from a distance.

This is not what he does best though, because to there was an aspect to the film that was excellent and this was the feeling of outdatedness, of an unnecessary function and a pointless "war". This feeling is in the characters, in the set-decoration and in every shot. The men we follow had the height of their import many years ago – now it appears they are mainly fighting their equal numbers on the other side simply because they exist. I really liked this overarching sense of smallness that sat across the film and I enjoyed finding it being employed in even the smallest detail – in the attitude of a minor character through to the cheap "do not unplug" text scrawled on the wall (those that work in older offices will know this feeling). Alfredson is bang on the money with this feeling, it is part of the story and it is brilliantly delivered throughout.

Speaking of brilliant delivery, the cast is deep in British talent and unsurprisingly they deliver. Oldman may not have won the Oscar but he is great here – working with restraint and doing so much. He does so much with minor reactions and movements and he is a great character. He is the lead here but alongside him is a cast that is hard not to just list – Cumberbach, Hurt, Jones, Firth, Burke, Graham, Hardy and so on; British all perhaps but it says a lot that almost all of the supporting players here will be recognised internationally. Everyone gives strong performances and everyone seems to understand what Alfredson is doing.

Overall, this is a great film albeit one that is not as easy to follow as those impatient snobs would have you believe. It is OK to struggle with some aspects and it is still easy to enjoy the film. The plot engaged me but what stayed with me more than anything else was how it all seemed so unimportant, how those involved were all working to ignore the irrelevance of their work and how very tired this world seemed – this aspect was very well done and made the film as much as Oldman's strong central performance.