Peer review
Non-physics content: Detailed-information about kwanggari of different era, providing us with a clear development process.
Physics Content: Well done on the physics component of the article. However, maybe add a little more information - for example - some theory related to the reason why kwanggari is a non-harmonic instrument.
Clear Explanations: Most of the content explained in depth and really well!
Structure and Length: It's hard to point out any deficiency of the structure, the length of the project is arranged pretty well~~
Diagrams and Photographs: I think you guys are good for this part by adding motion graph to make the content more vivid, but actually I think the last two diagrams are more related to Chinese luo, rather than kwanggari, so how about add some spectrum of kwanggari to your project?
Good job!