This movie taught me that, similar to how "Attorney Woo" made me more understanding of people who are on the autism spectrum.
The love story was quite amazing because of the acting, especially by Shin Hyun Been. The love spilling out of her eyes whenever she was looking at Jung Woo Sung was gloriously sweet. The humanistic love came across loud and clear. The fact that Jung is 13 years older than Shin didn't bother me at all, unlike other dramas that also feature a big age gap between the lovers (e.g. Goblin, Mr. Sunshine.)
The attention paid to creating the artwork for the story was very impressive as well. If those paintings really exist in some art gallery in Seoul, I'd love to go see them.
I have one complaint - the soundtrack. For 2/3 theme songs, why are so many verses in English? Either write an English song with someone who can sing with virtually no accent, or just sing a Korean song. Don't keep switching between the two from one stanza or verse to another. The heavy Korean accent made it hard to tell if the singer was singing in English or Korean at times, which just makes it worse. Other than that, the instrumental soundtrack is excellent.
Overall, this movie was very entertaining to watch and definitely worth re-watching.