Campaign Concept - Hong Kong underground

[Daigoro]

I can't take credit, they're mostly cribbed from various movies.

My recommends, if you haven't already seen them-
- Infernal Affairs- just watch I, I found II and III a bit dull and derivative
- My Father is a Hero
- The Killer and Hard Boiled- of course, but you've already mentioned John Woo

More character possibilities, or extra twists for those above-
- an otherwise eager, loyal and high-ranking gangster whose secret is that he's giving information to the police, or to another triad
- an old friend of the undercover cop, who has had plastic surgery and wouldn't be recognised by him, has gone deep undercover, perhaps to settle a personal vendetta (from Rogue Assassin/War)