A strong performance from McAvoy and a fairly well-constructed first two-thirds make this worthwhile, but it derails and becomes a bit silly and absurd in its final third

Rating: 6/10 (18 November 2017)

Three girls are kidnapped by a man with Dissociative Personality Disorder (with a total of 23 personalities). The girls try their best to escape from said individual, but little do they know the fate that awaits them when a new 24th personality is said to emerge in the very near future...
In Shyamalan's latest film he throws us into the main plot of the film more-or-less straight away which in one way is good (we don't get a long and potentially dull build up prior to being thrown into the kidnapping itself) and bad because there's no development of the principal protagonists. On balance, the set-up provides more good than bad; whilst I found that I didn't care much for the protagonists as people I did care for the situation that they were caught up in which meant that I did find Split to be a fairly involving experience overall..
I think one slight problem with films that explore D.I.D or any other personality disorders is that sometimes it's hard to perhaps give them the true justice that they deserve... I think that in order to make them truly compelling, terrifying and realistic the filmmakers would have to explore each personality on more than a superficial level in order to make this aspect work, but in an average 105 to 120 minute film you don't really have the sufficient time to accomplish this goal. This is perhaps one reason why films focusing on personality disorders of say two or perhaps 3 different personalities arguably work better as there is more time afforded to each personality. By attempting to cover a multitude of personalities, Shyamalan's narrative unfortunately lacks depth as we never really learn a great deal about the various personalities...
Whilst Shyamalan's narrative may not be quite up to scratch thankfully the same cannot be said for his directing which here is actually superb... The isolated setting is put to good use and Shyamalan also gets one hell of a performance from James McAvoy - some of his personas are chilling whilst some of his personas show a vulnerable side to him and he's so convincing that you sometimes forget that this is all done by the same person. The film is also well-paced with plenty going on and few, if any dull moments.
There are parts of the film where one of the girls is trying to manipulate one of McAvoy's weaker personas in order to effect her escape. This was an interesting part of the story and the film probably would have been stronger if this was utilised more in the film... perhaps if all 3 girls worked together in trying to achieve this or maybe if they tried playing the personalities off against each other. If you think about it I'm almost certain that this would have made the film stronger as there is already something of a power-struggle between some of the personalities which would have been exacerbated had the girls managed to manipulate the necessary personalities. For me, this would have made the film more involving and would have perhaps had me on the edge-of-my seat a bit more. However, Shyamalan seems to put most of the focus on McAvoy's personas either intimidating the girls, discussing power struggling and the 24th personality in therapy sessions or sermonising on the reasons that the girls have been chosen; these things are strong enough to make it work, but I got the feeling that a bit more effort the film could have been better.
Sadly, the film does derail slightly into the absurd in its final third; in fact it becomes so silly and ridiculous that it becomes hard to take it seriously - which is odd considering the film is about an individual with D.I.D and one wonders why Shyamalan felt the need to drag the film in a silly direction given the rather serious subject matter?
Still it is a pretty solid film and whilst it's not in the same league as Shyamalan's earlier films such as The Sixth Sense or Unbreakable it is much better than The Visit which Shyamalan released a year earlier than this one.