I love how the scenes from the present are presented in a cool blue tone while the scenes from the past are presented in a more sepia-toned so it's not very confusing. I like the characters but I think Detective Cha is too serious and too aggressive in her acting. I don't have a favorite character yet, as I feel I don't know much about them yet. The first part is a bit slow and boring for me, the tension surging up only when Detective Park discovers the walkie-talkie—then it was boring again, the tension surging up once more when they had the "lead suspect" almost cornered.I hope the next episodes won't disappoint me. I have watched a few dramas where the first episode is a bit slow and dragging but far exceeded my expectations during the next episodes, like Strong Woman Do Bong Soon. I have high expectations with Signal, given its high rating in this platform, so I'm not dropping it for now.