While I do believe this drama is a complete masterpiece, set out to keep you from endless nights of no sleep, it does end with a bit of plot holes filled in a messy manner.
The character's ability to capture the audience, especially Do Min Joon, is very well written and always keeps me on the edge of my seat.
The ending is rather disappointing as I had high hopes, so it didn't live up to the overall amazingly written plot from the beginning. It felt like they slapped a bandaid over a battle wound. At least that's my opinion.