It can't be said that the quality of the lectures is lower than other lectures.. The examples and lecture scenarios are well prepared.. The explanations are not clear, but they are natural enough to be necessary, so it doesn't feel like a waste of time... The problem is that some lectures are not recorded properly, but considering that this is a serious defect in the online lecture product and there are solutions, it is difficult to give it a good evaluation.. Since the real-time lecture situation is not recorded or the sound sources are not diverse, it is possible to record only the problematic parts separately and easily edit only the sound parts, but I think it shows the irresponsibility or incompetence of the platform called Inflearn that it ends with a notice telling you to check it in advance... This is a problem with how they view students who invest time and resources, and what attitude they are currently treating them with.. Except for second-hand transactions, can it be said that the seller has fulfilled their responsibility and duty just by writing 'Be careful, there are some defects' near the product when selling it? It is natural to repair defects or resell after recall, and if it is impossible due to cost issues, at least considerable efforts should be made to minimize consumer damage, such as writing caution notices very large or repeatedly notifying them. Since it was free, it ends with this level of complaint, but how absurd must the students who purchased this course be...