The Space Adventure Trivia
The original Japanese title, "Densetsu no Otoko", means "Legendary Man". Remnants of this title are still visible on the title screen of the US and PAL Sega CD versions, where Cobra is called "Legendary Bandit"...
"The Space Adventure" is probably the only game that made it out of japan based on "Space Adventure Cobra" a manga series created by Buichi Terasawa in 1977 and published on Shonen Jump Magazine. Gaining tremendous success as an offbeat, sexy space James Bond-type adventure series, Cobra's adventures lasted until 1984 with both a movie ("Space Adventure Cobra: The Movie") and a 31-episode animé series produced by Tokyo Movie Shinsha in 1982(which is pure gold I tell you! Go get it!).
In 1995 Terasawa revisited his most successful creation with a new manga series titled "Cobra: The Psychogun" published in Super Jump (a more adult-oriented mag. than Shonen Jump) which features computer generated backgrounds and photoshop-ed colors. An animé adaptation of this series was almost produced, but the company in charge went bankrupt at the last second, dammit.
Extra, ultra-nerd useless trivia: Before the original animé series was produced a pilot episode was completed in english with the hopes of selling it internationally, however that wasn't meant to be and the episode never got distributed, making it a collector's item, as it not only remains unreleased but also has a slightly different visual design and style than both the movie and the series.
The Chopin piano piece that Jane likes so much and that you should play in order to hear her message at a certain point in the game, is Etude op.10 no.3 in E Major. Chopin himself considered the main theme of this etude the most beautiful melody he had ever written.
In the Turtle, Cobra's space ship, there is a computer shaped like a piano (or a piano with computer functions, as Cobra says himself). Jean will ask Cobra to play something for her. The piece Cobra plays is the famous song Ständchen, also known as Serenade, from the song cycle Schwanengesang by Franz Schubert.