I first watched this movie about two years ago. It is one that has stayed in my mind ... it is disturbing, somewhat provocative, fascinating, thought provoking and definitely metaphysical. I thought the production, the cinematography and acting were excellent. Altogether they did a wonderful job conveying with some pretty intense emotional states/events. It is a very loaded movie.

In short:
The movie takes you into Tam's life and into his state of mind. Both his real world and his mind are pretty horrific places. I wouldn't call the movie a romance by any long shot but there is definitely something "other worldly" and surreal about it. Tam's life is definitely not aspirational. His family constantly told him he was defective because he was gay, that he couldn't be trusted, that he needed to make them proud and care more for them, even though they couldn't care less about him. Having to live with that all your life and to then have the shit kicked out of you at school is enough to do anyone's head in.

Tam was literally caught between a rock and a hard place with no escape ... except to escape into his own mind ... it is his safe haven, but it is so distorted in there ... is what he sees in his mind a reflection of outside reality? Is the 'reality' outside the only 'real' reality ? ... is the 'reality' inside one's mind fake even though it is 'so real' to the owner of that mind ?. Tam's mental reality and the reality of the outside world is so blurry ... so much so that at the end of the movie, I think the only "real" things were Tam himself and the murder of Tam's family in the lounge room ... the rest ... well that is the proverbial metaphysical question isn't it ... which reality is the 'real' reality for Tam ?

More detailed:
The imagery / symbolism throughout the movie were very evocative and beautifully captured the essence of an altered mind state. There were quite a number of images/scenes that really left an impression on me (I have put the old "Spoiler" cover on as you may want to see the movie first) and influenced the conclusions I arrived out watching the movie:

(1) The algae on the pool walls and in the washroom - so many of them looked like human images to me ... it was kind of like a Rorschach ink blot test. Were these representatives of people in Tam's life? He tried to scrape off one ... I wondered who that might have represented to him ... his Father ... it was right in the centre of the pool wall? Towards the end in the washroom, I really thought the algae on the wall was Phum and as Tam walked back into the wall and rested next to it I thought wow ... is Phum even real? Was the pool facility some kind of giant Rorschach ink blot test for Tam?

(2) The clouds. The clouds in the movie were magnificent and there were a lot of scenes where they formed the major portion of the scene. There was one significant cloud panorama where this massive cloud had hidden the sun and all you could see were the striking crepuscular rays coming through ... it gave the impression that I was on the dark side of something and the light was trying to break its way through the clouds. Was this the case for Tam's mind?

(3) Looking up at the sky while underneath the water. Again this was fascinating ... like the clouds, the water was a barrier to being able to see clearly. Water is a distortion of light and therefore the images scene through it. Also all the waters that Tam sunk beneath were dirty - there were bits of muck floating around and mosquito larvae swimming about. I don't know about where you live but where I live Mosquito larvae are harbingers of disease e.g. Dengue, Ross River etc. Does all of this suggest a "diseased" perspective of Tam?

(4) The blue light. I think there is a connection with this blue light and the name of the movie. The blue hour is the period of twilight in the morning or evening when sun has dipped below the horizon and the sunlight becomes a blue shade of colour due to "Rayleigh Scattering". People who have spiritual beliefs say that the "blue hour" is the moment between dreams and awakening. It is also known medically that blue light affects/has caused depressive moods in people. That is why the medicos advise to have less screen time before you sleep and why companies like Apple have an option to decrease blue light emission on phones etc. So was most of the movie just a strange dream in Tam's mind? Was there any part of it that was real? Which lead me to the next point ...

(5) The Fight Club. Because of all of the above elements, I thought of the protagonist in the Hollywood Film "The Fight Club". Was Tam the equivalent of Edward Norton's character and Phum was the equivalent of Brad Pitt's character?

At the end of the movie, I think Phum was imaginary. I think the only "real" things in the movie were Tam himself and the murder of Tam's family in the lounge room. His family constantly told him he was defective because he was gay, that he couldn't be trusted, that he needed to make them proud and care more for them even though they couldn't care less about him.

Having to live with that all your life and to then have the shit kicked out of you at school is enough to do anyone's head in. He was literally caught between a rock and a hard place with no escape ... except to escape into his own mind ... and to get rid of the "ink blots" who had hurt and betrayed him so much when they should have loved and nurtured him and cared for him.

Aside from his most likely imaginary lover Phum, he could have developed a multiple personalities as well ? ... the one that kicked back against the oppression, the one who stole the Buddha, who stole the gun, maybe even one was the murderer?

Who knows. What we do know is the final scene of the movie ... he and Phum both sunk beneath the very dark waters of the river and looked up. Against the light of day, he saw bits of muck floating in the water ... mosquito larvae and the blurry images of the blue sky and clouds ... the delusion continues to be his 'safe haven'.

A fascinating film on a whole lot of levels.