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There are origami unicorns placed throughout the levels. These unicorns are a reference to the film "Blade Runner", directed by the original Alien movie director, Ridley Scott.
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William Hope, who played Lt. Gorman in the Aliens film, voices Marshal Waits in the campaign. The character is also modeled after his physical appearance.
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At one point in development, it was planned for the Working Joe enemy to quote lines from William Shakespeare in a malevolent manner. However, it was ultimately decided it didn't fit with the tone of the game and the few recorded lines were cut from the game.
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There are a few references to the original movie.
1. Scattered around the Torrens and Sevastopol station are drinking birds. The first one found is in the hypersleep chamber.
2. During Mission 2 in the baggage claim area, players can hear the faint sound of meowing before it abruptly stops as they approach the primary airlock. This is a possible reference to the cat Jonesy from the first movie.
3. Another reference is found when players discover the deceased Alistair Smythe who has a rolled-up magazine shoved down his throat. Spoiler:This is how Ash tried to kill Ellen Ripley.

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