Tunnel got a lot of comparisons to Signal in the beginning and I can see it a little bit. I don't think it was quite as good as Signal, but I still enjoyed it a lot and looked forward to it every week. The story was engaging and the characters were written well. I enjoyed the dynamics of the 3 main characters and how they interacted with each other. As with all time travel shows, there are a few plot holes, but nothing major enough to detract from the show. Choi Jin Hyuk did a wonderful job as Park Kwang Ho. He put a lot of emotion into his performance and really twisted my heart for him and how badly he wanted to catch the killer and get home to his wife, Yeon Sook. Yoon Hyun Min also played Seon Jae well, and his progress as a character was interesting to watch. Same for Lee Yoo Young as Shin Jae Yi. She started out almost robotic, but it was a quirk of her character and not due to bad writing. When her shell finally cracks open, she is a sympathetic character. I have nothing but praise for all the cast - excellent work! The music was good, nothing stand out, but enjoyable all the same. This one isn't really suitable for re-watch as the suspense is gone after you've seen it once. I would definitely recommend it to fans of the shows genres.