Episode 14 is not a substitute for the original Balanodon episode in the 1974 series. It is actually a combination of two unfilmed concepts, one planned for the original series, and another conceived by Matsumoto and while it was never filmed, it made it into a manga — and worked into one of the PS games.
The first — originally slated for the series (and ended up in Akira Hio's manga adaptation) — was the story of Iroze, a female Gamilas assassin (basically a
Kunoichi or female ninja), who sneaks aboard the Yamato and begins to kill members of the crew, which causes a ruckus since those aboard the ship believe that one of their own is a killer, until she is ferreted out and disposed of.
The second — which was a rejected concept of Matsumoto's was "The Eternal Story of Jura", which was published as a stand-alone manga in
Play Comic magazine. The story concerns a pointy-eared alien — romantically linked to Dessler — who's daughter is used to exert mind-control over the Yamato and drive the crew mad (like the Sirens of Greek myth). The story ends on a very tragic note.
Sample page (translated for the now-defunct starblazers.com)
You can watch the entire sidestory manga, here:
http://www.veoh.com/watch/v20521869Eeq3Gm2r