One of the two .22 target pistols in the movie is a Russian Margolin Olympic target pistol. The same type of pistol used as Princess Leia's laser pistol in the Star Wars movies. The other pistol is a Luger .22, elements of which are found in Jan Erso's A-180 pistol.
The song being played as the performers in the Safari Club rehearse, and while Isaacs and Marissa Wiegler talk, is "The Devil Is in the Details" by The Chemical Brothers. Isaacs actually references the song title during the dialogue.
When Hanna learns about DNA on the computer in Berlin the montage of images includes: a small detail of the Hell panel of Hieronymus Bosch's "The Garden of Earthly Delights" (c 1490-1510); the Vacanti 'earmouse' (1997); and 1884 zoopraxographic frames of a running man by Eadweard Muybridge (1830-1904), one of the earliest pioneers of cinema.
The trivia item below may give away important plot points.
The first line and the final line of the movie are the same, spoken by Hanna, each time after she fires an arrow into her target's torso: "I just missed your heart" followed by Hanna aiming and firing a pistol at the camera (her target's point of view), then transitioning to the "Hanna" title screen.