* ExecutiveMeddling: The European version of this game was heavily marketed by Nintendo of Europe as a ''VideoGame/BrainAge''-style puzzle compilation instead of an adventure game with quirky characters, to the objections of Level-5 president Akihiro Hino. This is best demonstrated by its cover art: While [[https://images.nintendolife.com/games/ds/professor_layton_and_the_curious_village/cover_large.jpg the American version]] is similar to the Japanese cover and focuses on the characters and setting, [[https://www.celjaded.com/wp-content/uploads/2019/02/CelJaded-Professor-Layton-and-the-Curious-Village-Box-Art.jpg the European version]] pushes Layton into the corner and emphasises the puzzles instead. In the end however, [[Administrivia/TropesAreTools this turned out to be a good thing]] as Europe became Professor Layton's biggest international market by a wide margin, and all future American covers take cues from the European ones.
* OrphanedReference: The awkward half-staircase that just leads to a bookshelf in the Reinhold Manor ([[spoiler:which also doesn't really obscure the fact that the bookshelf hides a secret room]]) exists because earlier versions of the room had that staircase lead to the lounge. In the final game, the lounge was moved upstairs, a change which also possibly explains why [[spoiler:Don Paolo was able to leap from the lounge's window and escape without injury]].
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