Successfully complete the game to unlock the powerful but slow Star Glider ship.
Atlantis, 2015 level
Get 100% in a repair on the Twin Fighter or any electronic-based
repair mini-game after level 5 to unlock level 6, "Atlantis,
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Italy, 1502 level
Get a "Air Virtuoso" or higher rank on level 11 to unlock level 12, "Atlantis, 2015".
Strategy guides from GameFAQs