Adaptation Displacement: Many fans of the musical are unaware that it was based on this movie, and thanks to the Frank Oz movie, people may accidentally rent the Roger Corman version, or try watch it online, not realizing which film it is, and sometimes complaining that it's not the Frank Oz movie.
Nightmare Fuel: The scene in which the plant's flowers open. The cartoonish sound effects did not help.
One-Scene Wonder: Despite his limited screen time, Nicholson's appearance is one of the most popular scenes in the movie. A testament to the popularity of this scene is the fact that it was cut out of the musical, but written into the screenplay of the Frank Oz movie, where the role is instead adopted by Bill Murray, under a different character name.
Padding: Like many Corman flicks, this one has tons of walking scenes... and running scenes!
Retroactive Recognition: The big one is Jack Nicholson, who was an unknown when the movie was originally released, and now gets top billing on most home video releases, even though his role, as memorable as it may be, is very small. Dick Miller and Jackie Joseph are the second and third most recognized cast members, due to their later roles in Gremlins. Fans of Mystery Science Theater 3000 may recognize Jonathan Haze and Mel Welles for their roles in a couple of different movies shown on that series.