The show has 4 episodes of 30 minutes each, so it's like a 2-hour long movie. The drama is quite good, although there wasn't much going on and the story is nothing out of ordinary.

The good:
- Fluffy and mature with nice characters.
- Unexpected good chemistry between the leads. I've nevem imaged Kim Seon Ho and Lee Yoo Young together, but I was surprised and impressed with the couple.
- It's nothing new to praise Kim Seon Ho acting, but he was great once again. Lee Yoo Young was also great, as I could not image her playing the lead in Tunnel. It was like two different person.
- Raw emotions with cohesive dialogues and discussions. Real adult with real problems.

The bad:
- Supporting characters? Just to help the couple notice each other. It was a cheap way to make the leads relationship change a bit.
- The first 2 episodes were gold, but the last two were a lil' draggy and some overextended scenes. This is probably because of the 4-episode format. Maybe if it was movie the execution would be better?
- I would like to see more of the working life of the leads. But it is understandable.
- Aaahh, that ending. Why do short dramas love time skip? I just don't understand. The leads have the confession time where BOTH said they like each other. But then then FL says that this will break up their friendship and then just cut all contact with the male lead for a year? What? I understand her worry of starting a romantic relationship with the best friend. But give up without even trying and staying away for a whole year? And then she just comes back and that's it. He was waiting for her for a year. Everything comes back to normal and now they are dating. Very unrealistic.

Overall, it's a good drama to watch when you have nothing else to do. Sit and enjoy the ride. Even if you are mad at the end, you at least enjoyed the couple's chemistry.