Many people were quick to call bullshit in regard to Kugel's "endemic disease." And among those were people who correctly guessed that he was actually a simulated personality by Striker the moment he started appearing as a hologram.
The second OVA covers what Kugel did when he was on Earth. He was found by a pirate fleet, and the main girl he saved ended up dying from a disease, likely tuberculosis. He too began coughing up blood at the end, and with her death, and Striker's constant influence, he starts succumbing to Sanity Slippage before he too dies from the disease and his "will" is carried out by Striker.
Science Marches On: When Chamber brings up a planetary map of the solar system, it also includes Pluto, which is classified as a Dwarf Planet today and not a planet proper. The same holds true when, in the files Ledo look at in Episode 9, a newscaster shows a planetary map that includes Pluto and Halley's Comet alongside the regular planets.
What Could Have Been: There were plans for an anime sequel but due to "various circumstances", it was scrapped and the sequel became an upcoming Light Novel.
Super Robot Wars: The series made its first appearance in in the Super Robot Wars Z 3: Tengoku-hen. Incidentally, not only did the staff of Gargantia apparently want it to appear in the series, but the staff of SRW were planning on including it even before it finished airing.