Canon is a term used in media works such as comic books, novels, movies, television shows and even fan works. Canon can connect events together such as stories, games, etc. With little or no mistakes and continuity errors.
Canon can be an easy thing to work with or it can be a pain in one's ass, with things going out of order and out of whack. People and writers can be picky on what is canon and what isn't. Stuff littered with plot holes and Dis Continuity are not canon. Debates and mud slinging is bound to happen whenever canon vs non canon is up at bat.
- Everything must connect. With explaing how characters or things have gotten there. Pulling ideas out of thin air really isn't an excuse.
- Crossovers are not canon. It depends.
- Age differnces are canon. Example, Zero is 16 years old, Indy is 36, Billy is 16 years old, Crash is 20 etc. Changing ages of the characters like keeping Zero 16 and Billy 34 is not canon. Nor it will ever be.
- The up coming "Chose your own Adventure" are canon. They tie up lose ends and fix errors.
- Viroid being captured by Captain Shuu is canon, as well for Viroid's story on how he was captured.
- Glace and Di brutally beating up Red to the point of death and tieing him up is canon, as well for Zero and company rescuing him is canon.
- Events with copyrighted characters are not canon. Which pretty much sums this.
- Cartoon characters in a war torn world are NOT canon. Nor ever will be.
- Red's insanity happening from being a project of JOSEPH is canon.
- Kai's Royal Blood is canon.
- Zero visiting Crash on Earth is canon.
Now you know.
What ifs can be a senario. It can pretty much lean towards canon or non canon, but may or not do any harm to canon. Fan games and crossovers are excluded out of What If senarios. Common what if senarios are orgins of how Dallas earned her scar, how Tanuko forged her eye patch or why Indy has a western name.