Both movies are about a guy who falls in love with his female best friend.

It isn't the storyline which makes those movies similar, but the fact that both are tragic movies. Plus they have an awesome scenery. A Millionaire's First Love is shot in a way that you can feel this wonderful atmosphere and so is Classic.

Both have to do with kidnapping a popular star!

'Dog' turned human romance story. Chul Soo (Song Joong Ki)'s character is like a wolf that suddenly gained a human body [yes he is a werewolf but this is how his character acts] where Shiro (Toyokawa Etsushi) is shown to be a guide dog given a human body to find the girl that raised him as a puppy. If you liked one you'll probably like the other.

Both story concentrates on the main actor with mental instability. A grown up men with a mind of a young child. Happy and carefree.

Both are live-actions and are about survival games. Who's the best? Who will win the game ?

The same story but the difference is that one is a drama and the other a movie. The drama is more elaborated than the movie and new actors

They are both about memory lose illness

Both have a history of rivalry and confrontation between the two protagonists in addition to tell one parte of the history of ancient China.