I only decided to watch this drama because I'm from Spain and it was set in Granada. I'm not a fan of Hyun Bin, and even if I've seen Park Shin Hye more than four times already, I can't get to like her acting (and my opinion unluckily does not improve in this one).
First of all, it was strange to see a Korean drama in the streets, trains, buildings that are so common for me. On the other hand there were some incoherences for a Spanish watcher (as to see the train lines in Catalan language when they are in the South of Spain, or that many of the Spanish extras in the drama had latin american accent). I'm aware that Korean people would never know all this, but I think the production could have done a better work.
I liked the story very much, all the action around the game and the augmented reality. It was really good. I didn't like at all the pseudo romance, it was completely unnecessary.
About the acting, Hyun Bin was really good. The drama is about him, and he does what he should do. On the other hand, Park Shin Hye’s role was unnecessary too. She does not add anything to the story nor she helps the male lead in any way. And, moreover, they could have chosen somebody who could speak Spanish (as Seo Ye Ji who at least studied at the university in Spain). Nobody could believe that someone who had been in a different country for 12 years could speak the language so bad. Even her brother Se Jo was much much better when he spoke in Spanish.
I didn't expect anything else from the ending, so I can't say I'm disappointed. I don't think either that the male and female lead happy ending would be a good ending… but I understand the bad reviews about this though.
If you want to watch something slightly different, with a new sci-fi story, a lot of action and different settings, go for it. But don't expect too much from it.