It's rare today for a horror film to respect its audience as much as 'Possum' does. Horror films that ask their audience to concentrate, think and solve are becoming less and less popular. All people seem to want is the fast-food horror that 'The Conjuring' universe spews out 3-4 times a year. And that's fine if horror isn't the genre you go to when you're looking for a heavy and deep film, but I would suggest you are missing out on some rare treats like 'Possum'.
What's going to hurt this film with audiences the most is that it is admittedly very slow. A lot of the dialogue is cryptic and there is basically no action. Despite this though I found I couldn't take my eyes off the screen. It was almost hypnotising in a way. I was determined to work out exactly what the film was trying to tell me.
The film asks a lot of you. First of all to understand what it all means, and then to understand a twist through that same lens. I was fairly confident I had understood most of it, but I did read an explanation thread on the film afterwards just to be sure I had it right. Needless to say this film won't be for everyone, and some could even argue this isn't really a horror film, but if you feel like a challenge I'd recommend giving it a look.