This drama was really really REALLY good! The story, the acting, everything was amazing. And yet I felt like there was something missing. But I'll talk about that later. Story: The story was really good! A high school student pretending to be a 27 year old office worker seems absurd but it was totally believable. The mystery surrounding Lee Min Suk's brother was very intriguing but it wasn't the main focus of the drama and was only dealt with in the few last episodes. The drama focused on Lee Min Suk and how he grew as a character. The noona romance was okay too though I wasn't that invested in it. The star of this drama for me was Lee Min Suk. I went in thinking it was going to be like City Hunter, you know a quest for revenge and everything. But this turned out to be completely different. This drama wasn't intense, it was cute and funny. I loved how they used old drama cliches and gave them a twist to make them funny or different. I especially liked that Yoo Jin Woo's story was progressed along with Lee Min Suk's and he was given his due importance too.The story was very well-written and the pace of the drama was really good. Characters: Seo In Guk did an amazing job as Lee Min Suk (and Lee Hyung Suk). First of all, I've always acknowledged that Seo In Guk is good-looking but during this drama I realized that he is gorgeous! Especially as Lee Hyung Suk (even though he appeared for like 1-2 episodes). Secondly, Seo In Guk is an extremely talented actor! And this role showed his talent to the fullest. He played the role of a high schooler so well, unlike someone else (Lee Min Ho I'm looking at you), that it was hard to believe that in real life he is 26. Lee Min Suk was endearing and funny and adorable. But I also loved the scenes where he got all serious and mature. I loved seeing him grow from a boy into a man! Seo In Guk's portrayal of both brothers was so good you could see who was who with the way he stood and talked. While Lee Min Suk was kinda sloppy, as expected of a kid, Lee Hyung Suk stood with confidence. Where Lee Min Suk talked in a cheery way, Lee Hyung Suk's voice was grave and serious. I simply loved Seo In Guk's acting in this drama! Jung Soo Young is a character I would rather not talk about. She was uncomfortably painful to watch. I understood her character really well and I got where the writer wanted to go with her but Lee Ha Na's portrayal of her was not good. Jung Soo Young is a character I could have loved had Lee Ha Na did her justice. Soo Young is a socially awkward girl with seemingly no talents. I get the character. It was Lee Ha Na's job to make that character relatable, even likable. But the way she played her it felt like Jung Soo Young had some mental disability. Which was really very uncomfortable for me to watch. But of course, I did get used to her and then she didn't bother me much. But I never felt connected to her. I did feel sorry for her but only a little. I loved loved LOVED Lee Soo Hyuk as Yoo Jin Woo! I loved how this time the broken bad boy was not the male lead but the second lead. And Lee Soo Hyuk played him really well! And did I mention how gorgeous Lee Soo Hyuk is?!! Because he is really gorgeous!! I could stare at him all day! I loved his story arc and how it all played out. I loved this broken bad boy with a good heart! But I never, for one second, believed that he was actually in love with Soo Young. I felt like he needed someone and since Soo Young was previously obsessed with him he figured she would be a good person to keep by his side. I never felt like he actually, honestly loved her. All the minor characters were great! The office people were your typical office people, gossiping and judging. They also provided very good entertainment. Team Leader Kim was very funny and so adorable! Jo Han Chul did an awesome job playing him and I loved seeing him onscreen! I loved how he cared so much about Lee Min Suk and all his anxiety breakdowns (I seem like a bad person saying I enjoyed his breakdowns but really, they were funny and added for comedic purposes). Jung Yoo Ah (Soo Young's sister) was super annoying at first but like her sister she became tolerable. I loved Lee Min Suk's friends! They were so supportive and super funny, with their chuppa chuppas and stuff! Lee Min Suk's dad was awesome! He wasn't his real dad but he cared so much for him that it was heartwarming and so beautiful. My favorite though was Min Suk's grandfather (his adoptive father's father)! Kwon Seong Deok was amazing, playing him and he was so funny and adorable and it was so heartbreaking! I really loved him! I loved how the minor characters played a more important role in this drama than they usually do in dramas. Romance: I honestly believe Seo In Guk has good chemistry with everyone. Be it a girl or a boy, he has good chemistry with all. Just look at his previous works. He had amazing chemistry with Jung Eun Ji AND Hoya in Reply 1997. Even as a second lead he has awesome chemistry with the female leads (see Master's Sun). It was no exception in King of High School. He not only had great chemistry with Lee Ha Na but also with Lee Soo Hyuk! BUT I was not as much invested in the romance and the main couple as I would have had it not been for Lee Ha Na. The couple wasn't all that bad but they couldn't pull on the strings of my heart like the InHyun couple (Queen In Hyun's Man) & the Reply 1997 couple (Jung Eun Ji and Seo In Guk). So that 'something missing' thing I was talking about was my lack of love for the main couple. Ending: The extra episodes really weren't needed. But I didn't mind them much. Most people are not satisfied with the ending and to be honest if I would've written this I would've ended it differently too but it wasn't that bad and I don't have much of a problem with it. Overall: All in all this was a really good drama and most people might not have the problems with it that I did so I highly recommend it for anyone who is in the mood of a good rom-com.