I'm just in LOVE with that noir thing, the gangsters, the policemen, the undercover guys... Does anyone have a suggestion? City Hunter and Bridal Mask both gave me a feeling like CC, but now I'm out of similar dramas o-o
Hmmm, maybe the time between a wolf and dog? Jung Kyung-Ho is also the main character :D (bonus ... LOL) and the currently airing Two Weeks, kind of feels like Heartless City and (the man from nowhere) to me. hope that helps :)
There's plenty. But I recommend you what I enjoy the most --> Fugitive Plan B,Ghost,IRIS,Myung Wol The Spy,Time Between Dog and Wolf. I don't know if you already watch any of this or what ur personal preference is but I hope it help :)
these little dramas seems similar http://mydramalist.com/korean-drama/4013/holy-land
http://mydramalist.com/korean-drama/2911/little-girl-k
Then there is Death Note and Bloody Monday and perhaps Black and White

I would also suggest Bad Guy and Ilijimae

though none of them are as Humphrey Bogart esque as Cruel City
holy land - its filmed pretty darn gritty and its all fighting / gangs the devil - about cops and revenge and its also filmed pretty gritty bloody Monday 1 and 2 - cops trying to save japan along with hacker high school boy time between dog and wolf - more of a mainstream version of cruel city movie - infernal affairs - pretty much same story uncover cop and dirty cops (departed is remake)
I checked your list and I see you haven't watched Lovers, http://mydramalist.com/korean-drama/1069/lovers.
I'd highly recommend it. Not necessarily a gritty noir like Cruel City, but if gangsters and amazing fight scenes are what you're looking for, then Lovers certainly delivers. Plus if you like a healthy dash of romance thrown in, this is one of the best I've seen! :)
I haven't gotten around to either of these yet -- one of them is going to be my next drama -- but I'm told Lobbyist & Rondo are also decent action/crime dramas.