Here is the full list of all 8 Heart and Seoul achievements. It takes around 0-1 hour to unlock all of the achievements on Windows.
Achieve all endings
Reject Seok-Jin
Seok-Jin confesses his love for you
Choose to return to Daegu
Choose to stay in Seoul
Reject Hyun-Woo
Get Hyun-Woo confesses his love for you
Choose all the "funny options" during the job interview