The main men at UFO, Peter Chan and Lee Chi-Ngai, team up for this off-beat but affecting time travel movie that's more about characters than time travel. Tony Leung Chiu-Wai plays Yuen, a shallow real-estate salesman who resents his father Feng (Tony Leung Ka-Fai) for being too giving and philanthropic - and for not being overly successful in life. Yuen calls his father a 'loser,' and the next thing you know Feng is in the hospital and stuck in a coma.
Then it's fantasy plot-device time. Yuen gets whisked back in time and meets his father as a young man. Yuen figures he can act like Marty McFly and change the future by mucking with the past. Yuen's mother Laura (Carina Lau) was once the heiress to a large fortune, but her dad (Chor Yuen) disapproved of Feng, and Laura ended up chucking the cash for her future husband. Yuen tries to make his family rich by making Feng palatable to Laura's father, thus insuring that his future will be taken care of, too.
Unlike the nifty reformatting of time that Back to the Future glorified, He Ain't Heavy, He's My Father chooses a different path. This UFO film is about reconciling and appreciating the past, and using it to find hope and fulfillment for the future. In that, the film shows remarkable human sentiment as it asks that people change, and not the circumstances that create their lives. It's a message that seems tailor-made for Hong Kong residents (whining about the handover will get you nowhere), but it's also a lesson that anyone, anywhere, can relate to.
UFO has never been shy about making their messages evident, but they manage to do so in charming, enjoyable ways. The film is engaging and quite entertaining thanks to its low-key mixture of sci-fi, comedy, and maudlin family drama. Writer-director Lee Chi-Ngai throws some of his usual satire into the film with appearances by future HK notables, including Waise Lee as a young Lee Ka-Sing. That and other in-jokes can slip by the less seasoned viewer, but they don't detract from the film's charm.
The actors are uniformly good, with Tony Leung Ka-Fai standing out as the sometimes cartoonish, but always endearing Feng. He and Tony Leung Chiu-Wai work extremely well together, and Carina Lau, Anita Yuen (in two roles), and Lawrence Cheng turn in fine support. The film does stop for some brief HK-specific asides, i.e. musical numbers and situation comedy wackiness, but the uneven means never detract from the film's ultimately enjoyable whole.