Board Thread:General Discussion/@comment-33480874-20170101232001

Canon by definition is anything that is considered "real" in a fictional universe. So if something is not "real", it's not canon. Obviously, Sega and  Nintendo characters that have crossed over with Sonic are considered non-canon. If this is the case, this pretty much means that these crossover games are also non-canon, and by extension, anything unique/exclusive in them, such as locations (Sunshine Tour), objects (Fog Machines), or abilities (Plasma Attack), would also be considered non-canon. 