In the film's last scene, Lenny gets into a car with bandaged hands, but the bandages are missing during close-ups of his hands holding a framed photograph.
The bike Lenny rides to get help is not his; it is Marty's "Road Master" bicycle.
Lenny is at the store with a broken bike when the radio reports that a storm is coming, and Hedy takes him home. Later, when Lenny is playing cards with his aunt during the storm, they talk about how the broken bike was left at the store. When she goes into labor, the phone is dead so Aunt says, "Get on your bike!" And now the bike is at home.
Lenny is sent to his uncle's house in Queens for the summer. There is a scene of him and a friend riding their bikes in the neighborhood, and in the background is a large suspension bridge which looks like the Verrizano Bridge--which was built in 1964. Since the movie takes place in the late 1950s this bridge obviously was not built yet--and when it was, it was built in Brooklyn, not Queens.
Lenny refers to the comic book "G.I. Joe" when Hedy almost catches him hiding in her closet. The "G.I. Joe" character/action figure was introduced in 1964 and the related comic book much later. Since the story was set in the 1950s, Lenny could NOT be reading G.I Joe comics.