The Japanese still raped and pillaged Nanjing/Nanking to the extent that Little Boy was required. This is documented in history. There's a sugar coated film for the West about it.

"Nanking" tells the story of the rape of Nanking, one of the most tragic events in history. In 1937, the invading Japanese army murdered over 200,000 and raped tens of thousands of Chinese. In the midst of the horror, a small group of Western expatriates banded together to save 250,000 -- an act of extraordinary heroism. Bringing an event little-known outside of Asia to a global audience, "Nanking" shows the tremendous impact individuals can make on the course of history. It is a gripping account of light in the darkest of times.—Anonymous

For A Chinese own website Reddit (And by proxy KiA) sure do like to cover up the atrocities of history in the Far East. This video game being one of them.