Like Quentin Tarentino, Pedro Almodóvar loves to display his love of cinema in his own films. In "Bad Education" the cinema tribute is seen in two ways that when understood help give the viewer an understanding of what exactly is going on here.
The first way is that characters in the movie go to the cinema twice. The first time is to see "Esa Mujer," a movie I admittedly am not familiar with but whose first plot keyword on its IMDB page is "Melodrama." The characters next go to a cinema that, if judged by the posters on the wall, is having a film noir festival.
Almodóvar tips his hand in associating "Bad Education" with melodrama and film noir. It's no surprise then when he find hallmarks of these genres like heated and complicated love affairs, and murderous intrigue.
The other cinema tribute is that the story of "Bad Education" concerns filmmakers and their collaborating on a movie. So yes, there's a movie within a movie. In this case, it's called "The Visit."
In "Bad Education," "The Visit" is being directed by Enrique Goded (played by Fele Martinez) who grew up in a Catholic school with the writer and star of "The Visit," Ignacio Rodriguez. Or that's what Enrique thinks. Enrique soon discovers that Ignacio is actually dead, and the person who claims to be him now is Ignacio's younger brother, Juan (Gael Garcia Bernal). Still, Enrique follows through on the making of "The Visit," which has certain dramatic parallels to Enrique and Ignacio's lives.
The viewer is given different perspectives throughout the film: Enrique and Ignacio as children; Enrique and Juan (who is pretending to be Ignacio) as adults; the characters of "The Visit" as children and as adults; and then the perspectives of the former priest at the school where Enrique and Ignacio grew up, Sr Manuel Berenguer (Lluís Omar).
Like I said, it's confusing. But fret not, film viewer. Sure, you can dock a point for not the strongest ending to a film in the world. But Almodóvar's skill at creating compelling characters is still in full force, and his cinema send up is appreciated. But more than that, by creating movies of such high quality, they themselves are the best tribute he can ever make to cinema.