Where to begin. The good: The plot line of the bullied kid looking to the tough karate girl for help and joining the karate school was fun enough. Nothing too original but it was executed alright. The fights were okay. A number of times you could clearly see the punches/kicks didn't even come close to connecting. That's a common problem in less serious movies with martial arts though so forgivable. The bad: Is casting 25-30 year olds as high school students still a thing? It was distracting how not high-school age the main guy was. The girl was alright. She's older than she looks so almost passable. The guy playing Hae-seong stood out so little there's not much to say about him. He was fine. The music in some scenes was downright inappropriate. Like in the tea scene. This ominous, foreboding music like something really serious is happening. Except it wasn't. The whole gangster storyline seemed really tacked on and largely irrelevant. It seemed to come out of nowhere and if it were cut out completely and the Jin-hyeok guy were just the 'boss bully' or something it would have been a lot more fun. The gangster stuff wouldn't have been missed. The movie was about 30 minutes too long. A comedy of this type stretched to 2 hours is tough to sit through. Lastly, I was really, really hoping 'the warmup dance' at the end WOULD just be a kata, and was pre-emptively cringing. Then he started doing a kata and I thought alright. And then surely enough, right into the stupid, annoying dance, giving this film it's finale cliche moment and leaving a rather bitter taste in the mouth. It would have been so much better if he had merely sold it as a 'dance' while just bringing in a traditional kata without the students really realizing it, sort of easing them into being true karatekas.
Final verdict: 6/10. There was potential for a nice, simple underdog meets teacher and overcomes the odds story which became bloated and overly confused. Don't regret watching it, but once is more than enough.