RacerS2 has released a tweak for Sleeping Dogs that lets you play the open-world game in first-person, instead of the game's default third-person view.
While you couldn't play the game to completion like this - melee combat would be all but impossible - it certainly ramps up the level of immersion you get from United's digital version of Hong Kong. Which sounds good to me.
The third-person view forces the player to fixate much of their attention on the player avatar itself, meaning a lot of the more incidental detail in the game world is rarely noticed. Drag the view in like this and suddenly the streets look, and feel, more alive.
You can grab the mod yourself at the link below.