I can describe Glass as an entertaining experience, but not solid enough to be an appropriate closure of the Unbreakable-Split-Glass trilogy.
While I can see what Mr Shyamalan wanted to do, I don't think he managed to deliver with the characters and the plot the necessary complexity to answer all the questions the audience raised in the previous two movies. Many things have been left unanswered especially about Kevin, while David Dunn is just a shadow that doesn't do much in the movie.
The real star in this movie is supposed to be Mr Glass, but not much about his past is told, either. Everything is absurdly summarized in a way that, in the end, we don't really know - or care - about who Mr Glass or Kevin were. There isn't enough character development or closure going on here.
Sarah Paulson's talent was wasted on a character who could be played by anyone. She is a brilliant actress but the character was poorly written and brings nothing new or dramatically useful to the plot.
Cinematography is fine just as the pacing of the movie. Like I said, it is entertaining, definitely - and perhaps it will please the audiences who are used to the almost shallow plots of superhero movies. But if you were expecting a more deep and challenging story about humans with supernatural powers, you will be disappointed.
In the end, Mr Shyamalan couldn't make a superhero movie, and couldn't make a deep, mind-bending metaphysical movie either. He merely brushed over both worlds, but didn't dive deeply into either of them. It is a pity that a plot that had potential and that showed up to be brilliant in "Split" had such an underwhelming and unremarkable closure.
