Sheng gang qi bing 4: Di xia tong dao (1990)

The final entry in Michael and Johnny Mak's Long Arm of the Law series, Underground Express once again tells a story of gangsters versus police, focusing on the difference between how both factions act depending if they're coming from Hong Kong or Mainland China. There's some decent action that delivers a high body count, but the rushed production and editing that was obviously and clumsily done to avoid a Category III rating regulates this to being just another average Hong Kong cops and robbers flick.