%%ZCE%%* AllStarCast: Both the original Japanese and the English dub feature veteran voice actors.
* BreakthroughHit: ''VisualNovel/{{CLANNAD}}'' was the first major license for Creator/SentaiFilmworks after the demise of Creator/ADVFilms.[[note]] It was actually initially announced as an ADV title and was planned to have a release like ''VisualNovel/{{Kanon}}'s'' – neat boxset, dub, etc. Kyle Jones, director for ''Kanon'' and ''VisualNovel/{{Air}}'', even did a preliminary casting call. Shortly thereafter, thanks to a combination of the worldwide financial crash and ADV's legal troubles (read its page), it became clear that successor company Sentai [[NoBudget would not have the operating capital to do such a lavish release]]. So they bunged out a bare-bones subtitled-only DVD that was slammed by critics for a dry translation and multiple typos. Despite that, it sold beyond their wildest dreams. So well, in fact, that when it came time to do a rerelease, they had enough money to give it a dub… although they had to use a less expensive director (Steven Foster) and had far less time for script polishing and recording than they were used to.[[/note]] The English localization of the VN also raised the profile of its publisher, Sekai Project. The success of the VN's fundraising prompted Key to localize several other of its major visual novels in turn: ''Tomoyo After'', ''VisualNovel/LittleBusters'' and ''VisualNovel/{{Rewrite}}'', both on their own and in collaboration with Sekai Project, after Key [[NoExportForYou previously said they weren't interested in exporting their VNs to the Anglosphere]]. Their 2016 visual novel ''VisualNovel/{{Harmonia}}'' was in fact released in English shortly ''before'' its Japanese release.
* CashCowFranchise: Starting as a visual novel, ''CLANNAD'' has become a multimedia project, spawning manga, an anime film and TV series and drama [=CDs=].
* CrossDressingVoices: Kappei Hiiragi, Katsuki Shima and Yuu.
* TheDanza: Kyou. Not quite, but close enough to be confusing. Her name is Kyou; her {{Polar Opposite Twin|s}} is Ryou; her {{seiyuu}} is named [[Creator/RyoHirohashi Ryo]].
* ExecutiveMeddling: It was Key that insisted on the DRM in the physical edition of Sekai Project's localized version of the VN. Thankfully, after coming to an agreement with Sekai Project later on, the physical editions were launched DRM-free.
* FandomNod: The ''VisualNovel/{{Clannad}} After Story'' anime answered a much speculated question in the fandom: What happens if Sanae's Bread meets [[VisualNovel/{{Kanon}} Akiko's Jam]]? "It's the ultimate combination!"
* LateExportForYou: Prior to Sekai Project's release of an official English version in late 2015 (on Steam, no less), the VN was one of the most frustrating examples of NoExportForYou, given [[GermansLoveDavidHasselhoff the popularity of the anime]] in the West.
* NewbieBoom: This happened with the anime. Despite the fact that both ''VisualNovel/{{Air}}'' and ''VisualNovel/{{Kanon}}'' were popular, this series ended up attracting more fans than the other two combined. This led to a large group of ''Clannad'' fans who were largely independent of the Creator/KeyVisualArts fandom, who hadn't even ''heard'' of the earlier works (and didn't feel obligated to check them out). This happened again with ''Anime/AngelBeats'' a few years later.
** Averted in the West, where – for the most part – those interested in ''Clannad'' were fans already familiar with the earlier releases of ''Air'' and ''Kanon''.
* ScheduleSlip: The original VN was announced in 2001 with a 2002 release date, but it only came out in 2004.
* StarMakingRole: The anime's English dub put both Creator/DavidMatranga and Creator/EmilyNeves on the map. Granted, the former was already a well-established voice actor but he gained further fame with Tomoya (and both [=VAs=] would eventually gain even further fame in several Creator/FUNimation dubs afterwards).
* TroubledProduction:
** The VN was originally slated for release in 2002, but Key took until 2004 polishing up the scenarios. The development suffered lots of setbacks, including one of the scenario writers getting stabbed partway through.
** Narrowly subverted during the production of the official English version of the VN by Sekai Project. A glitch in the translation software they were using accidentally deleted all of their progress up to that point. A backup of their work was thankfully on hand, and production could continue as planned.
* WhatCouldHaveBeen:
** Yukine was supposed to be a main heroine in planning, but was demoted to a secondary character as her story did not match expectations. This is why she's featured on some cover art for the visual novel alongside the other main girls, [[AdvertisedExtra despite only being a minor character]].
** Sanae was originally going to be overweight in her early character design, but was slimmed down to give her a more youthful appearance. The designers considered having an option to fatten her up.
** The Fujibayashi sisters were going to be saved from a burning school building by "Clannadman." Jun Maeda came up with this scenario after the original writer for the route was stabbed and had to spend some time recuperating in the hospital.
** Kotomi was going to be an EmotionlessGirl.
** Fuko was going to be a more serious character, before she was changed into the comic relief. This change possibly spared her life, as the conclusion of her route seems to have been originally written under the premise that she passed away.
* WrittenForMyKids: The reason this was an all-ages game was so that Key's president could create something his kids could enjoy, as opposed to the adult [=VNs=] the company had been known for up to that point. He also says that the anime was a labor of love for Creator/KyotoAnimation as well.
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