Just before Butters comes downstairs with his "Hitler," a hidden alien can be seen blending in with the back of Kyle's chair.
The episode parodies several movies of the 1980s, most of all Better Off Dead (1985) starring John Cusack. In Better Off Dead, Lane Meyer (Cusack) was teased by Roy Stalin with pig noises and challenged to ski the K12. In South Park, Stan was teased by Tad with chicken sounds and challenged to ski the K13. Tad's inflections in his voice very similar to Roy Stalin's as well.
The "montage" song, played during Stan's training for a ski race is also used in Team America: World Police (2004). The lyrics are slightly changed though, to fit in with the movies' story.
Though the character Mr. Slave doesn't make his first official appearance until the episode entitled "The Death Camp of Tolerance" (S6 E14), his voice can be heard singing the song "Take On Me" by A-ha during the end credits of this episode.
Last scene, the girl's mutant human-faced breasts say, "Quaid, start the reactor." Twelve years before this episode was made, the movie Total Recall (1990) had a diminutive conjoined twin named Kuato telling Quaid to start the alien reactor that would convert the massive ice deposits of airless Mars into a breathable, albeit insanely explosive, atmosphere.