Making it as two parts was totally unneccesary, I can understand "two seasons drama" when time between first and second season is long, not when they are basically released at the same time as in this case. I have watched first part because of Cha EunWoo - and he did really good in this drama, and because I like fantasy. I like second part better but it is still wasted potential of the plot, cause it could be easily one of the best drama that year.
I rated it pretty high but even if you do not watch, you will miss nothing.