A great and fun series, it's based on the same online writings as the Korean movie of the same name. Some of the events that happen are as they happen in the movie, while others aren't in the movie but are in the online writings. Since the movie is one of my favorites, I had to give the manhwa a try. It was very much as enjoyable as the movie was.
Geon-woo is pretty nice and sincere in his efforts of healing the girl's heart, but he can have his moments of course of...thinking like a guy? But he knows better and controls himself. The girl - whom isn't really named - can be rather demanding of Geon-woo and sometimes sinister in her plots. However at the same time she has kind of a sadness or vulnerability deep down that can sometimes also be seen. There are some random other characters that appear at times, but they're the two main ones.
As for the artwork, the series is in full color and doesn't exactly have the "usual manga look" which kind of took a little to get used to at first, but wasn't hard to and is still pretty good. At times when Geon-woo or sometimes other characters get mischievous and such, they're drawn with a bit more of a comical look to them. There's a little bit of a running theme of "toilet humor" and throwing up at one point which I'm not as into but it's not really all that bad or anything. Overall the art is good and seems fitting for the series and its style.
There's a downside, but it's not really about the series itself. Just the fact that after the first five volumes the series was dropped by the people releasing it and there haven't been any new volumes since 2005. As well as there seeming to be no plans of any more of it to be released which can be frustrating, of course. But never the less it's a great and very enjoyable series that is still very much worth giving a chance to read.