Bok Geo-il, author of the source novel Bimyeong-eul Chajaseo ("Looking for an Epitaph") (1987), refused to be associated with the finished product, and successfully sued the film-makers to have his name removed from the credits.
The film takes place in 2009.
2009: Lost Memories (2002) was a co-production between Korea and Japan, coinciding with the 2002 FIFA World Cup, held jointly in Japan and South Korea.
In about the 48 minute on the right hand screen an image of a damage building can be see. The building depicted is the Bijlmer flat in Amsterdam, Netherlands that fell victim of the crash of El Al flight 1862 on October the 4th 1992.
Interestinly, the cars in Korea in the film are shown driving on the left side of the road, with the steering wheel on the right. This differs from real-life South Korea, where vehicles drive on the right and have the steering wheel on the left which is how most of the world drives. However, this is not a error. The film takes place in an alternate history where Korea remains a part of the Japanese Empire, and this driving orientation is a deliberate world-building detail reflecting Japanese influence, as Japan drives on the left.