Kind of same vibes, slow-paced drama. Both FL are mistreated physically and mentally. In Hide and Seek, there's an enemy to lovers relationship and although the romance is not the main plot of the drama, it's still present.

As soon as I watched Money Heist, it reminded me of Pied Piper. Both dramas deal with negotiations but Pied Piper is mainly focused negotiation with people in order to prevent bad things from happening.

Similarities:
-A team of people (police) against the injustice of the wealthy people.
-The suspense of not knowing what is going to happen next.
-A mastermind criminal.
-Romance (although in Pied Piper is very minimal, it's still there)
-Good acting and action scenes.
-A terrorist attack.

Both dramas involve a fair amount of action and an interesting plot, with romance. Both Male Leads are great at fighting, too.

Both are action dramas that also involve romance, and both male leads help, save or rescue the female lead.

Although the setting is in no way similar because K2 is all about action and fighting scenes, the part about the male lead taking care of the female lead is the same. In Liar Game, the male lead takes care of the too-kind and naive girl through the entire drama. And even though there is not romance, there are little hints about a relationship between the MCs.