Long Arm of the Law 4 (1990)

Long Arm of the Law 4 1990 / 省港旗兵4：地下通道 1990 / Long Arm of the Law IV: Underground Express , Sang Gong Kei Bing 4 , Sheng Gang Qi Bing 4: Di Xia Tong Diao , 省港旗兵第四集地下通道 ,

The 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. (Source: IMDb)