A Retcon (Retroactive continuity adjustment) is the alteration of previously established facts within the continuity of a fictional work.
EGS is pretty good in this regard, with lot of things obviously planed much sooner than when they appeared. Still, there ARE some cases where Dan decided that it's better to break continuity, and there are others where he thinks about it. One remarkable point is that he is not trying to hide those cases from the readers: in fact, he points them out.
Actual Comic Changes Edit
The Power of Pheromones Edit
Dan's original notion of pheromones the FV5 will have was little too optimistic, as mentioned in commentary of EGS Main Story Comic for 2002-06-14 ("An Explanation Or A Complement?"). He later decided that they are not powerful enough to overcame Sarah's heterosexuality and EGS Main Story Comic for 2002-06-30 ("Stupid Lunch Trays Make It Impossible To Tell That They're Walking") was changed so Sarah and Elliot did NOT actually kissed. Original version is still linked from commentary.
It also wasn't powerful enough to overcame Susan's ... well to make Susan behave out of character at EGS Main Story Comic for 2002-06-27 ("Affection From The Hammer Queen") and call Elliot "cutie" and "honey". Although this may also be related to overall deepening of Susan's character. Again, original version is still linked from commentary.
Canonicity Changes Edit
Matt and Rat Edit
There are not supposed to be any fourth-wall breaking stuff in Main Universe except the introductory story line. Well ... there is. Specifically, Dan originally put Matt and Rat, his characters from earlier comic, into the Main Universe. He did not (yet) actually changed the comics itself, but refused to acknowledge it being canon in commentary and later pretended panels with them don't exists.
Temporary Changes Edit
For several hours (judging by timestamp in filename, between Fri, 11 Mar 2016 20:29:02 GMT and Sat, 12 Mar 2016 02:51:39 GMT) the comics on EGS Main Story Comic for 2013-01-21 lost last three panels. The commentary still referred to missing panels, so it didn't seemed like deliberate change. Because Dan referenced the gauntlet on that day's NP, SeriousJupiter noticed the same day. (current (fixed) image, shorter image, original image.) Dan's reaction  on being told about the missing panels was "Oh carp. It’s because I’m a dummy and tried to remove an outdated update schedule message and didn’t upload the double-sized version. Fixing ASAP, thanks for telling me." (mentioned in same thread by Scotty).
Non-continuity so can be just said to be retconned changed Edit
Called speed record for retconning, EGS:NP Comic for 2017-07-19 was published and just few hours afterwards declared to contain obvious continuity issue and therefore be retconned out and replaced with EGS:NP Comic for 2017-07-21 with different explanation.
Ideas/Backstory Changes Edit
Elliot's Inner Demons Edit
Originally, Elliot had a lot of pent up rage that could be unleashed though a special move, making him significantly more powerful, but kinda crazy and out of control. These "inner demons" were mentioned in 2002, but later explained out. Then Dan forgot he already explained it and after getting the question again he again answered it.
When Melissa first appeared, she and Justin had simply gone out on one date and she'd become obsessed. Later, Justin's story evolved and with it also Melisa's role (also, Noah appeared). The whole backstory was then hinted about mentioning that it's retcon and finally fully explained in EGS Main Story Comic for 2011-01-31.
Ellen's Depressions Edit
Ellen had a pretty unhealthy lifestyle before starting school ... but it IS possible she was originally supposed to have depressions but Dan dropped it due to it being tone shift (see comment on that page).
The Skull Haunting Grace Edit
It might've been Grace's Lespuko parent, or maybe her Lespuko side she merged with (her form changed when the creature disappeared).
Painted Black Changes Edit
Painted Black was the first story EGS was supposed to have: everything before that was setting up for it. Dan provides whole storyline about how it changed from original ideas to how it looks. He doesn't add exact timeline, but it is possible that some changes were finished with comics already running; the secrecy of everything could've masked a lot.
On EGS Main Story Comic for 2015-06-08 Dan mentioned that he overdid the FV5 Ellen on EGS Main Story Comic for 2008-04-11 ("An Unexpected Complication") and since then is using the same effects in sketchbook, but that it's not consistent with how FV5 is supposed to function.
This is not completely clear, but it likely means he will start drawing FV5 Ellen with smaller boobs. Dan being Dan, he talks about it instead of leaving it be and hoping people will blame it on art change.
When Dr. Germahn explained the Hammers for first time on EGS Main Story Comic for 2002-03-13 ("Remember: REAL Hammers Do REAL Damage"), he mentioned that they can't be used if the situation is serious. Obviously, the situation Susan and Nanase were in in France WAS serious, so it seems like retcon that they could use them. Note that it can be argued that the mugger didn't do anything offensive, but the explanation was definitely retconed.
Liz Gets Magic Edit
Liz seems to get magic based on EGS:NP Comic for 2016-08-26 ... despite the fact that there was nothing about her having magic in earlier comics which happened after this one. On the other hand, Liz isn't featured on-panel enough for this to be problem ... probably ...
- ↑ EGS Main Story Comic for 2002-06-30 ("Stupid Lunch Trays Make It Impossible To Tell That They're Walking")
- ↑ EGS Main Story Comic for 2002-06-27 ("Affection From The Hammer Queen")
- ↑ EGS Main Story Comic for 2002-05-30 ("Wow... Freaky")
- ↑ EGS Main Story Comic for 2002-06-12 ("Hm? Say That Again?")
- ↑ egscomics tumblr post ID 140887787463
- ↑ 6.0 6.1 EGS Main Story Comic for 2011-07-08
- ↑ EGS Main Story Comic for 2002-04-14 ("Nanase VS Elliot")
- ↑ EGS Main Story Comic for 2010-02-04 ("Trying Too Hard To Realize The Camera's Still Rolling")
- ↑ EGS Main Story Comic for 2003-03-07 ("Meet Melissa")
- ↑ EGS:NP Comic for 2004-05-13 ("Not A Date At The Mall - Part V")
- ↑ EGS Main Story Comic for 2010-12-31
- ↑ EGS Main Story Comic for 2003-07-16 ("One Mystery Solved...")
- ↑ EGS Main Story Comic for 2002-03-18 ("A Nightmare And A Greeting")
- ↑ EGS Main Story Comic for 2002-09-11 ("Recurring Nightmare")
- ↑ 15.0 15.1 EGS Main Story Comic for 2004-01-14 ("Haunted Grace")
- ↑ EGS Main Story Comic for 2004-08-28 ("Grace's Dream, Part I")
- ↑ EGS Main Story Comic for 2004-09-01 ("Grace's Dream, Part III")
- ↑ EGS Main Story Comic for 2016-06-08
- ↑ EGS Main Story Comic for 2004-07-07 ("In the Beginning")
- ↑ EGS Main Story Comic for 2002-03-17 ("In The Shadows Lurk The Nightmares Made By Man")
- ↑ EGS Main Story Comic for 2004-03-01 ("The Purpose Of Grace")
- ↑ EGS Main Story Comic for 2010-05-28