I think the low rating (currently 5.4) is due to the fact that many viewers are used to getting a lot of hard action, combined with a fast pace from a South Korean movie.
In this movie, however, you get neither, and this seems to be absolutely unbearable for people whose attention span has been completely stunted, thanks to TikTok and other trash.
Of course, a slow narrative pace and relatively little carnage are not automatically a sign of quality. It always depends on what the director and the actors do with the script.
Thankfully, the best has been made of it in this film, so if you are prepared to engage with a slowly unfolding plot, you will be rewarded.
So if you want to see something other than a constant adrenaline rush in a South Korean movie, you should definitely go for it.
More of this, please. Much more!
P. S.: As always, I give a 10 to a movie whose rating is ridiculously low, just to do my part to at least minimally influence that rating.
My actual rating would be an 8/10.