Both of the shows have a mystery about actions of the characters..Both have characters that take actions for what they perceive is greater good and end up sacrificing themselves

Both deal with a time loop that gets activated with a certain event happening.both lead characters undergo a lot of changes

Directed by the same PD .While not similar plotwise,you'll find the direction quite similar..Also,shares a beautiful OST as well

1.Both are school based shows and are strong on romance.
2.Lot of focus on friendships and bonding
3.Both have a light pleasant feel to them

1. Both leads are twin brothers
2. Both leads roles get switched
3. Both come from different types of world- one privileged,other poor

1. Both leads are twin siblings
2. Both get switched at one point
3. There is an overall dark history binding the twins

Resurrection also involves a switch of twin brothers who are the lead characters due to circumstances .

1.Both leads are twins
2. Both are living different kinds of lives

1 Has a similar boss/secretary workplace romance
2. ML has been suffering from trauma and the secretary helps him