Continuity mistake: When the press secretary kisses the hand of the alien-dressed-as-a-seductive-woman, the eyeball ring is on her right middle finger but after she knocks him out (or kills him) the ring is on the finger between the middle and the pinkie. In subsequent scenes it's back on the middle finger. (01:01:35 - 01:04:20)
Factual error: Casey arrives at the desert landing in a jeep that is flagged with 4 stars (for a 4 star general) although he is only a 3 star general (as evident by the 3 stars on his shoulder boards). (00:33:30 - 00:35:25)
Chosen answer: While the movie is a parody of the 50's sci-fi B-movies, the film is actually based on the Topps 1962 science fiction trading card collection called "Mars Attacks!", which tells the tale of the Martians' attack.
Bishop73