"Same rules apply"

I think it refers to his inability to change the core of his personality and behavior-patterns, but I'm in the same boat as you; I feel like I missed something. To have that be the last line uttered by the protagonist in a film that's primarily a character-study following 1 man and his existence, the "same rules apply" line must have a deeper significance than the proclamation that he hasn't changed throughout all the events shown and his descent towards totally bottoming-out. Anyone have an more concrete answers?

I thought it meant that everyone is fair game in the sense that they're victims in the little web he was trying to spin where no one gets a happy ending but him, which in the end, turns out he doesn't get as well so the same rules apply even to himself. In my mind, the final "same rules apply" is kinda like a "guess the joke's on me after all" kinda thing.

I dunno if I'm oversimplifying things but that's how I see it.

I took it sort of as life is like a game and no one really wins and you can't control it

Bc one of the therapist scenes they talk about the games (I think it was when they were talking about his brother or something)

Spoilers:
At the beginning of the film he says: “The games are always, I repeat, always, being played but nobody plays the games like me. Detective Sergeant Bruce Robertson, soon to be Detective Inspector Bruce Robertson. You just have to be the best, and I usually am. Same rules apply.” and then he farts.

What happens at the end is that – when he’s about to hang himself – he sees two silhouettes by the door; not knowing that these belong to the young widow and her child, he mistakenly believes them to be his ex-wife and daughter’s. The silhouettes disappear, he says: “Same rules apply,” laughs and hangs himself.

The way I see it is that, up until this point he’s been playing the game by playing with with the lives of almost everybody else, at times only for his amusement; but when he sees the two shadows, he suddenly believes that there is a bit of hope, and then that hope is taken away from him; the “Universe” has played him, he became the victim of a “cosmic fart”, and why not? since the rules of the game applies to him as they do everybody else, he’s not above being played – he’s a part of the game just like everybody else is.

I thought it meant the same rules applied to him that applied to everyone because of the way he winked at us/the camera. He wasn't going to live just because things were finally turning around for him or because he was the main character. Like it would have for anyone else in the story, the chair snapped under his weight and his neck snapped / he died.

I like some of the other explanations here, though! I wonder if perhaps the book had more information on this? (There was a book, yes?)