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Importing a Chapter 1 save file to Chapter 2 after discovering the Original Starwalker results in the latter entering Kris' key items alongside Lancer and Rouxls Kaard, briefly exiting to accompany them at the carnival and appearing as part of the Thrash Machine's transformation scene.
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During the opening sequence where the player creates a "vessel," attempting to name their creation "Gaster" will instantly reset the game back to the title screen. Attempting to name yourself "Gaster," meanwhile, will cause the game to forcibly quit. This resembles an earlier Easter egg found in Undertale, where attempting to name the Fallen Child "Gaster" will similarly trigger a reset.
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Curiously, although recruiting enemies requires sparing or pacifying them, Spoiler:Jevil's bio mentions the Devilsknife item earned from defeating him violently, rather than the Jevilstail item earned from pacifying him.
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A subsequent patch chose not to remove the glitch, but rather introduce a penalizing Easter egg based on it, where Spoiler:firing six to ten charged shots with this exploit angers Spamton NEO and results in his attacks scaling up in damage with each successive use of the glitch.
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According to creator and director Toby Fox, the idea for Deltarune originated in 2011, when he had a literal fever dream about witnessing the ending to a game that didn't exist; upon waking up, he became determined to make that game a reality.
Development originally started the following year, but was put on hold before designing even a single room before the project resumed after Undertale's release; two of the songs originally composed during that initial stage would later be reused in Undertale as "Bonetrousle" (previously the main battle theme before being replaced with "Rude Buster") and "Heartache" (previously titled "Joker Battle", apparently being Spoiler:Jevil's early battle theme before being replaced with "THE WORLD REVOLVING").
Development originally started the following year, but was put on hold before designing even a single room before the project resumed after Undertale's release; two of the songs originally composed during that initial stage would later be reused in Undertale as "Bonetrousle" (previously the main battle theme before being replaced with "Rude Buster") and "Heartache" (previously titled "Joker Battle", apparently being Spoiler:Jevil's early battle theme before being replaced with "THE WORLD REVOLVING").
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According to Toby Fox, Susie was originally inspired by Maya Fey from the Ace Attorney series, being a similar "small, friendly, sassy companion" without any major tension. However, she was eventually changed into a more acrid figure as development progressed.
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If the player builds the duck version of the Thrash Machine in Chapter 1 and imports the resultant save file to Chapter 2, its attacks during the Spoiler:Rouxls Kaard fight become extremely easy to avoid; Spoiler:Rouxls and Ralsei will also have unique dialogue surrounding the machine's design.
Later, when the Thrash Machine is incorporated into the mech used to fight Spoiler:Giga Queen, the duck version replaces the standard punch sound effects with squeaking noises and features "DuckMode" as its offensive ACT, which reduces the move's strength in exchange for slightly draining additional health from Spoiler:Giga Queen between turns.
Later, when the Thrash Machine is incorporated into the mech used to fight Spoiler:Giga Queen, the duck version replaces the standard punch sound effects with squeaking noises and features "DuckMode" as its offensive ACT, which reduces the move's strength in exchange for slightly draining additional health from Spoiler:Giga Queen between turns.
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Furthermore, interacting with the toilet produces the message "(For some strange reason, a giant toilet-shaped toilet is blocking the way.)" This is a reference to the Iron Pencil statues in EarthBound, which produce the near-identical message "(For some weird reason, a pencil-shaped iron statue is blocking the path.)" when checked.
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