The first impression is based on the "Cantina Theme" heard in "Episode IV: A New Hope" from the Star Wars Films. If you are VERY perceptive, you may notice other themes hidden in the texture of the music as well (the Force Theme, Darth Vadar's theme, Yoda's theme, and various battle music motives).
The second impression is a very free interpretation of the "Force Theme" heard throughout all six Star Wars films.
While some impressions depart wildly from the source material, the third impression is an arrangement of the "March of the Ewoks" from the sixth Star Wars film.
The fourth impression combines themes from all six movies into a toccata of dramatic cacophony!