I was really surprised when analysing this fugue that I have played for many years to notice that it only contains one true complete fugal exposition, with the voices in all parts. It is still a strict fugue, but strict in another way: Bach concerns himself with treating a single piece of invertible counterpoint in all of the possible ways that it can be inverted, and with crafting episodic passages that use only limited melodic resources to achieve their task of moving between different parts of this fugue. Bach somehow continues to impress, even when you think you're already impressed...!