It is a film about those events in Japan, where foreign immigrants are avoided by the day-to-day society. They always mock Yakuza, and live in constant fear of being discovered and repatriated.
Shinjuku Incident forgoes flashy action scenes in favor of old-fashioned moralism. Warner Bros. could have made it in the 1930s, and that's a compliment.
Try as he might, strut as he does toward climactic showdowns with ruthless adversaries, [Chan's] character remains an incongruous muddle. Same goes for the movie.