Please don't watch this if you're depressed because it will drag you down emotionally. I could only watch the first 40 minutes (and that was by speeding through monotonous scenes, hoping beyond hope for more meaningful turns of events) before I quit watching. While many/most Chinese films have dark themes, this one is darker than most.
I'm still giving 4 stars because I don't know if the film ends with any encouraging/hopeful light - and maybe if you like dark themes, and aren't guarding your mental health, you might want to bear it out to the end to see. ( I unfortunately couldn't find ANY other critic reviews for this movie online, so I hope this helps someone.)