luckz

Some stuff happens at the end and it's up to the viewer how to interpret it. It's not an "open" (unclear/stops suddenly) ending but a "consider it to be how you want it to" ending.

The leads aren't 'together' before that, so them *never* actually getting together is a potential way to take it.

The ML seemingly throws an undercover cop off a building, to his death. Or at least we see the policeman fall to his death from a rooftop, and the male lead stands at the top of the building and reports "it has been taken care of" into his phone.

What is the point of this scene? What is the message? For the first 85% of the show, the ML tries very hard not to become a murderer. If he was one to begin with, more notably killing a policeman, what is the point?

At around 4 minutes into the first episode there's the first taste-of-things-to-come scene.

Cruel City was unnecessarily melodramatic in so many places...

Open ending, or something.

There was so much manipulation of evidence and willy-nilly non-investigation in this show, what you refer to is barely 10% of it.

The drama ends with a post-highlights ~8 seconds shot of the ML in a busy street wearing an out-of-character white suit and talking on the phone. That is the hint to him being alive, I suppose, though he looks gangsterish there none the less – and it doesn't make much sense that just a bit earlier his "ghost" appeared before the FL (in his old hideout).

The FL does not "like both MLs".

But here, it's more like 30% of the drug biz are actual police officers, or disgraced police-affiliated spies, or something like that.

Over here, at one point our far-right extremist party was so well-infiltrated that an alleged 15% of the leadership were police informers.

The writer's ill-conceived whodunnit from the early episodes ruins everything. It comes to an absolutely idiotic resolution and the last two or three episodes are far out there. I feel generous giving it a 5/10.
Some plot ideas get regurgitated so much that dialogue bits are copy-pasted as well.
The more Game of Thrones-y elements feel like they've been thrown in for pure shock value.
The OST variety is sub-par; the camerawork / direction / acting are fairly so-so. Every time I have excessively high hopes for a drama, they're crushed bitterly.

It's not really in any way shown, but also not exactly denied.
Maybe wouldn't have been "appropriate" TV material.

It's not just a "possible hint".

Where do you derive that from, besides maybe the ending shot with him wearing a white suit and talking on the phone?

Starts out as a C-drama.
Quickly becomes a non-stop Yakult advert with some HP product placement here and there.

(There's four different beverages that are peppered throughout the majority of scenes. Yakult is actually only one of them.)

The show never "really" decides what her "true self" is.

There's a hilarious scene in Thirty But Seventeen where the adopted animal, uhm, grows.

Given the premise is "the FL is impossibly rich, in an arranged marriage, and the ML is the snazziest idol singer in existence, and they are college deskmates because that was the only spot left", I'm not sure what kind of realism you expect from it.

There's one character who even gets a second loan later on, without his first one being paid off on-screen. ^_^

Counting tacked-on ending things there are four couples.
The other two are just thrown at you in the last episode.