Steam-what?

In Steamgothic, many elements of modern day society are found throughout the story. Leon states it is the 21st century and many modern elements are mentioned (Google, BMWs, iPhone, e-mail, etc.). To me, the only science fiction elements in the this story came at the end, but I am not sure what they are. How can this story be considered science fiction? What elements in the book constitute the stereotypical science fiction elements (usable technology, etc.)? What does Leon mean by only him and Louise remember 150 years that never was? Did they travel back in time?