I have no complaints about this drama. I think it does lack music compared to most of the dramas I've seen but I understand why, I think a lot of music in scenes wouldn't suit this drama. I love the storyline, I feel like I have a reason to suspect almost everyone. The cast is also incredible! Any drama starring Ok Taecyeon is a masterpiece and he's one of my fave actors, he's so versatile and expressive. Ha Seokjin is new to me and he's very impressive, especially the way his acting flows naturally. EunJi is also new to me and she did really well and made her character feel very real. Overall, I love the vibe of the drama. I love how everytime a new episode comes out, I understand more of the story but at the same time I start suspecting more and more people. Definitely worth watching for me. the plot has a way of making every character suspicious but at the same time not suspicious. There's great details and the way the actors portrayed their roles just made it even better. 9/10 at least for me. I know many people dislike "loop holes" but personally I dont care about that stuff. the drama is thrilling so I love it. Personally I kind of hope Sungjun (male lead) has disassociative identity disorder or like a spilt personality because sometimes he seems very evil to me and sometimes he feels very sincere. I feel like he also doesnt remember much at some moments.
I really like SungJun and SungHoon so far so I hope they expand on their relationship and I kind of want to see some wholesome moments between them. Anyway, I love how this show is going and I cant wait for next episode!

edit: after watching episode 4,5,6 I changed my mind. I dont like this show, I love it! I also love that Sung Jun always tries to joke around with his brother, I find that funny especially when his brother reacts awkwardly or seriously. I really like it, especially the scene when Sung Jun hugged his brother in episode 6 even though his brother didnt hug back. I hope to see more of their relationship and Im loving the story. Sung Jun is either the killer who had disassociative identity disorder and doesnt remember doing it OR he is just very unlucky and always just happens to be at the wrong place at the wrong time.

Edit: I finished this drama while it was airing but forgot to update my review. So my final thoughts are, I quite like teh ending. It did surprise me but I think it was fitting and I can easily conclude that blind is my favorite crime/mystery drama! Strongly reccomend. I know it has some plot holes, but it's a very fun and interesting watch for fans of murder mystery.