I’m kind of in the mood for something serious. I just watched these and really liked them:
Remember
The Innocent Man
Whisper
Distorted
Kill Me, Heal Me
SIgnal
Defendant
These are what I’m considering - from the Mystery/Crime Genre list of Viki’s
Love Me if You Dare
Ghost
I Remember You
Glass Mask (though it has lower ratings & over 100 episodes!!)
Arang and the Magistrate
or any others that are really engaging?
Of the ones you are considering I only watched I Remember You, which I really followed through.
This genre needs to get me right away, or I am out.
Maybe some of these dramas are worth a try:
https://www.viki.com/tv/22508c-beyond-the-clouds
https://www.viki.com/tv/20014c-two-weeks
https://www.viki.com/tv/23423c-bad-guys
https://www.viki.com/tv/28079c-heartless-city
https://www.viki.com/tv/34253c-mystery-queen
https://www.viki.com/tv/26896c-signal
https://www.viki.com/tv/24381c-pride-and-prejudice
https://www.viki.com/tv/33747c-tunnel
Totally agree:
TWo weeks awesome keeps you screaming in some episodes(At least I did)
Tunnel is really good. Loved it and loved the ending.
About your list of suggestions…
I liked I Remember You, but didn’t find it all that special in the end, despite loving all the actors. When it comes to Seo In Guk, I much preferred Squad 38.
I second @lutra whole-heartedly on the Heartless City and Bad Guys. Did not like particularly Pride and Prejudice. I hear Two Weeks and Tunnel are really good, they’re on my watchlist.
BUT, I would just add White Christmas, which I always recommend as an intelligent and thought-provoking thriller. The dialogues themselves are sometimes masterpieces on their own.
A good Chinese one (since I see you’re open to them) would be When a Snail Falls in Love (despite it’s deceptive title).
And finally, although I can’t vouch for it personally, since I didn’t watch it, but people go crazy when you mention IRIS.
Lot’s of great choices! Have fun 
Thank you! I’m going to watch all of these. I added them all and I’m watching Two Weeks right now. I want to watch Tunnel and Sparrow next. Sorry I was so late to say thank you. But I really do appreciate it.
