I've watched many light-hearted dramas recently and now I'm in the mood for some heavy stuff. It could be either a crime/mystery drama or a tragic/psychological one.
Some examples: Signal, Tunnel, Gap Dong, Boku no Ita Jikan, etc.
Remember: War of the Son Cruel City Duel Secret (2013) Lookout/The Guardians Liar Game (both Japanese and Korean versions are great) City Hunter Criminal Minds (Korean version) The K2
"Save Me" is currently airing and it's crazy. It's frustrating and makes you want to do all kinds of things to the cult. Agree with the dramas above as well. I especially enjoyed "The Guardians" and am planning to watch "Cruel City" as soon as possible. :)
If you want something similar to Boku no Ita Jikan you should watch 1 Litre no Namida (2005). It's probably one of the most popular tragedy dramas, and for good reason.
cruel city missing noir queen of ambition (very recommended) the winter the wind blows it's okay that's love secret beautiful life (Japanese) 49 days love me if you dare (Chinese) lee jun kai (Chinese) five fingers golden rainbow the devil shark last friends (Japanese)
Second Love Me if You Dare. It's a really great one, too.
You're All Surrounded was way heavier than I anticipated. It's also a crime/psychological drama. If you are interested in a heavy movie then I would recommend Always. It's a type of a production that makes you feel all sorts of things.
1 litre of tears Voice Contract Marriage Maou Kazoku game Liar Game Crisis: Kouan Kidou Sousatai Tokusou-han Ryusei no Kizuna Lookout Koizora I'm sorry I love you Nagareboshi Innocent man N no tame ni
White Christmas Secret Cruel City LIFE Save Me Ningen Shikkaku Last Friends Zeni Geba 49 Days Boku no Yabai Tsuma Lipstick God's Gift - 14 Days Kamisama Mou Sukoshi Dake Liar Game N no Tame ni The Quiz Show 1/2 The Village: Achiara's Secret Yume no California