For a start, the head is too big for the neck and the body the neck is attached to, which makes it appear as though the head is closer to the 'reader' rather than actually being a part of the body.
and I won't even get into the fact that this poster is almost exactly the same as the original with slight modifications. I think if anything that is what gives away the fact that it is a fake.
also, I know we don't really know much about the ramifications of pokemon cloning and the effects it can have on the survivors (thanks Gamefreak for NEVER going into that), but we would have to assume that because mewtwo wasn't created with a forme, he cannot exhibit the ability of having a forme which is an ability that only original pokemon have. However he was cloned from an original pokemon and not created from 'nothing', so it stands to reason that he COULD have a forme, but doesn't explain why this forme hasn't previously come about (Gamefreak will use some kind of item or place or 'bond' to explain it, that didn't previously exist)
