So, do they get in to medical school based on their Center Shiken scores?
Entry standards vary from university to university. Center Shiken scores will almost always be a factor, as will second-stage individual university entrance exam scores (nijishiken). But local quotas, recommendations, and personal essays/interviews are also typically part of the process. Many universities (particularly private ones) have feeder high schools which gear prospective medical students for entry.
I guess the Pre-Med system puzzles a few people from North America, but in many other countries, Medical School is an independant college that offers a Bachelors Degree and a license. So, if you were in one of those countries, to pursue a good career in research, you need a PhD degree even after you get your MD degree, and no, you can't really apply for a medical school after graduating a pre-med course.
Good Medical School Admission Essays - 386521 | …
One may also question whether the present examination system results in better teaching in schools. In fact, some teachers are so pressured to produce good examination results that they are forced to practise poor teaching methods. They may race through the syllabus, ignoring the fact that the weaker students have not grasped some of the concepts. Some other teachers may concentrate on popular examination topics, ignoring the topics which are rarely tested in the examinations.