The canon of the Destroy the Godmodder series refers to anything that exists in the same timeline as the first game, Destroy the Godmodder. This includes Destroy the Godmodder 2, Destroy the Godmodder 0rigins, and a small amount of spinoffs. All games in the main series are canon; spinoffs are non-canon by default unless a discussion with all Game Masters of canon games is held and they approve it.
If a game is canon, it has the ability to do nearly anything it wants with the timeline of Destroy the Godmodder and add onto its multiversal story in nearly any way. It can also interact with other canon games, although this has only happened once. The Godmodder is the antagonist of the main series, and Alpha is the antagonist of canon spinoffs.
Following the end of Destroy the Godmodder 2 and the subsequent release of Destroy the Godmodder 0rigins, Destroy the Godmodder's canon became massively complicated due to the multiple timelines, paradoxes, and other temporal shenanigans going on behind the scenes. The fact that Destroy the Godmodder: Terraria Edition was made canon while in progress only caused further problems. A Destroy the Godmodder reboot is in the works with the attempt to simply DTG canon, but so far, it has served to complicate the main canon even more.
After a concerted effort by Crystalcat to clean up and decomplicate the main canon, joined by other players at times and often opposed by others, the community eventually reached an overwhelming agreement to render all unfinished canonical games "loose canon". Destroy the Godmodder 0rigins, Destroy the Godmodder: MSPA Edition, and Destroy the Godmodder: Terraria Edition were affected. This has rendered canon much less complicated due to the nullification, for all practical purposes, of these games' various (and, at times, deleterious) effects on canon, while preserving the work of their participants.
List of Canonical and Loosely Canonical Games
Destroy the Godmodder
Destroy the Godmodder, being the first game as a whole and in the main series, defined DTG's canon. It set up the gameplay pillars that all other games, spinoffs or otherwise, follow. However, due to early installment weirdness, DTG1 isn't exactly the end-all be-all resource of information when it comes to plot.
Destroy the Godmodder 2
Destroy the Godmodder 2, being an official sequel that TT2000 granted permission on, is the second canon game and last chronological game in the main series (though not the last chronological canon game). It adopted the gameplay of DTG1 but also added many new gameplay elements moving forward, some of which have been adopted by other canon games. DTG2 set up the massive story that the series now knows, and it is considered to be the main source of plot alongside DTG0.
Destroy the Godmodder 0rigins
Destroy the Godmodder 0rigins radically departed from accepted DTG canon by introducing many new important plot points. The most important departure was the introduction of time loops - the idea that Fiction was continually restarting itself, with every iteration varying a bit more. UserZero was one of the only beings to be aware of these timeloops and retain memories between them. As a result of 0, Fiction looped over nine quadrillion times.
This fact, as well as the rampant chaos of the Dark Carnival, led to Fiction's spacetime becoming severely degraded. Time itself became a thick soup, which the Dark Carnival began looking to exploit. As a side effect, there were two alpha timelines - one in which the main DTG series was located, and the other in which a being known as the Black took control over reality.
DTG0 itself was located in the timeline after DTG's main canon, which technically made it chronologically the last canon game in the main series. The Zeroth War in DTG's main canon is, as such, undocumented by an actual DTG game, and its events can be left to theory.
DTG0 has been rendered loose canon due to being unfinished.
Destroy the Godmodder: TV Tropes Edition was the first canon spinoff. Chronologically, its events occur after DTG2, happening right after Alpha traveled through the Void in Act 5. Many characters from DTG2 also appear in this game as a result. Some of its events were also referenced in DTG2, and one of its events (the Paradox Dimentio fight) also occurred simultaneously in DTG2.
DTG:TV Tropes was assumed to be canon for some of its duration, which led to some conflicts between TwinBuilder and pionoplayer. However, it was officially confirmed canon following discussions with TT2000 and Twinbuilder. Alpha was created specifically to be the godmodder of this game, and to serve as the antagonist for all future canon spinoffs.
Destroy the Godmodder TV Tropes 2: Salvation was the second canon spinoff, created after the success of the first TV Tropes game. It continues directly after the events of the first TV Tropes game, although its events haven't leaked into other canon games yet. Because of the canon status of the first game, this game was automatically canon upon its release, although, due to it largely going unreferenced in other canonical games, it can be considered loosely canonical. It continued Alpha's rampage across TV Tropes.
Destroy the Godmodder: MSPA Edition was the third canon spinoff, created while TV Tropes 2 was going on. Its location in the timeline is unknown. It continued Alpha's adventures and also would have tied up the plotlines of Piono and Homestuck, which had been going on across many of the canon games. It is unfinished due to lack of players, and is now loose canon.
Destroy the Godmodder: Terraria Edition
Destroy the Godmodder: Terraria Edition was the fourth and final canon spinoff. It was originally non-canon, but after lengthy discussions with the canon Game Masters (and even Game Masters of non-canon sessions), it was decided that the spinoff had no reason to not be canon. It was known for its obscenely high power levels, so the game took place in a pocket area of the timeline. The game would have concluded Alpha's story arc.
The canonization of Terraria Edition led to some startling changes in the greater scope of DTG canon - primarily in the fact that Roxxanne's true identity as an incarnation of the Black became canonical, meaning that the Black is potentially present within DTG's main timeline, due to incredibly complicated shenanigans. Furthering the problem, its fourth and final GM, TrickleJest, transformed the game into an attempt at shattering an already-broken canon further for fun.
The game is currently dead due to the departure of its final GM, and has been rendered loose canon as a result (which handily fixes several problems with its canonical status, among which are the Black's canonicity and its final GM's attempts to, quote, "dance on the shards of canon").
Destroy the Godmodder 2's Epilogue: One Year Older
Taking place in the year after DTG2, the Epilogue was meant to chronicle the end of Fiction as the Narrative and Conflict engaged in the Final Conflict, destroying much of reality and battling until a stalemate, and the Godmodder prepared a portal to the Exception, a realm where he could initiate a reboot of reality to start back from square one. Although DTG0's established timeloop mechanic normally activates at the end of DTG2 (as in, the end of Act 5), these events meant that the end of DTG2 was at the end of reality itself, allowing all of DTG2's spinoffs (Alpha's story arc) to remain canon.
However, the idea that DTG2's timeline ended in a complete reboot of Fiction's continuity is at direct odds with the fact that DTG0 takes place in the timeline directly after DTG0. How this issue will be addressed is unknown.
Timeline of Canon
Any Destroy the Godmodder game that is not listed above is non-canon. If a game is non-canon, it does not fit into the main timeline of Destroy the Godmodder, and as such has no bearing whatsoever on its plot. Noncanon games can explore alternate timelines and scenarios, or can just reboot the core concept of the game with different characters on a different forum. There are some major spinoffs that are non-canon, but the majority of non-canon games are DTG copies found on other forums.