Sean Gilman’s review published on Letterboxd :
I'm still hung up on that list that called this a romantic comedy. I don't think it's either. There are some funny bits, but that doesn't make it a comedy. In fact, it's one of the most serious examinations of faith, and what it means to believe, of this century. And I am certain it is not a romance. Can't we allow Andy Lau's ex-monk and Cecilia Cheung's earnest cop to just be friends? Must romance be a necessary motivator for plot? I don't know why this irritates me so much. It seems like such a knee-jerk reaction, a failure to take the film seriously and deal with it on its on terms. Andy Lau in a muscle suit must mean that this is a wacky comedy. A man and a woman protagonist pair must mean this is a romance. Bleh.
It's hard. The film, more than even most To/Wai products, defies generic classification. And it is so ingrained in Western culture that realism = seriousness and vice versa, that any hint of fantasy or the supernatural tells us to read "comedy" or fluffiness. And to be fair, To and Lau set us up for this the last time they put him in a big suit, for 2001's Love on a Diet, which is most definitely a romantic comedy (albeit one with a darker tone than that label implies). But this film is not that film, and Lau's suit here, certainly non-realistic, does not serve as a punchline. It's a signifier of his moral state, the monk trying hard to believe but unable to get path the death of his friend, unable to let go the physical world. At his turning point, he decides to accept the demands of karma, he sees the logic in the philosophy, but he can't believe in it. He rejects the life of the monk and enters the real world and so his physical form becomes inflated, pumped up by the desire, the need for revenge and his inability, his religious unwillingness to take action.
This conflict is at the heart of so much Hong Kong genre cinema: the demands of loyalty and duty versus the commandments to withdraw from the world, to let go of material things. Running on Karma is one of the most deeply felt, most dense works on the subject, the culmination of Wai Ka-fai's mystical explorations, perfectly melded to Johnnie To's moody genre exercises. I know the intention behind including it on the romantic comedy list is good, and nothing said in the description of the film is completely wrong (well, other than framing their relationship as romantic, which, argghh) but it still drives me nuts. I need to let it go.