In the scene at Roosevelt Park when Jay firsts spots Emily and declares, "I am going to marry that girl," it is a reference to the fact that actor Ewen Wright (who plays Jay) and actress Laurel Butler (who plays Emily) were dating and talking marriage at the time of production. They have since gotten engaged.
Throughout the film Ash is almost always wearing a shirt featuring a comic book hero. These are just some of the many references to heroes throughout the film.
Nearly all of the film's dialogue is improvised. Ewen Wright wrote basic outlines for every scene, but most actors were asked to develop the dialogue on-set, with the camera rolling.