Complex sentence: Many of the songs came about for use with the animated film "Heavy Metal" such as the song "Vengeance (The Pact)," however only the song "Veteran of the Psychic Wars" ended up being used for the film.
Split into simpler sentences: Many of the songs were intended for the soundtrack of the animated film "Heavy Metal" such as "Vengeance (The Pact)". Only the song "Veteran of the Psychic Wars" ended up being used for the film.