Alternate Universe is or are non canon stories and events not connecting to canon. Can be sometimes called "Personal Canon" or "Fanon". Examples can be fanfiction, differnt story lines, or crossovers. Fanfiction and fan works tend to fall under Non canon or Alternate Universe. AU events have no connection to canon events. There would be alot of open wounds and errors galore if they were. Headachs galore!
Fan games can be pretty much fall under this or fan games with copy righted characters. Sometimes parodies of the said characters can skirt your way out of danger. Glace and Voltage are parodies and TAKE THATS to Eddie Leborn's Megaman fan film. With changes in personailty, actions, etc. Much like Transfromers comics poking fun at another transforming robot franchise.
Most fanworks are for fun and sometimes can fall apart faster than you can feed Zero his undon ramen. Even fanworks need to make sense, than just having a character appear out of thin air or why a character is much older than the other character when they were the same age last year.
Crossovers are not canon to anything in Scrawls; nor ever will be. Just like with fanfiction. No matter what you say.