Disclaimer: I haven’t actually seen the Birth of Mewtwo, so this is all coming from someone who knows the story at second hand.
(For anyone who doesn’t know the story: Amber was the daughter of Mr. Fuji, the dude who runs the Lavender Town Pokémon shelter and headed up the team of scientists who originally created Mewtwo. Amber had died as a child, and Fuji’s real aim in the project was to clone her; Mewtwo was just a gimmick to convince Giovanni to fund him. Mewtwo’s telepathic abilities allowed him and Ambertwo to converse while they were growing in their pods, and the cloned girl was his only friend. Unfortunately, while Mewtwo’s incredible powers kept him alive while he grew to maturity, Ambertwo died before she became strong enough to leave her pod. Ambertwo encouraged Mewtwo to believe that life is something to be celebrated, but his grief at losing her should probably be taken to be at least partly responsible for his massive existential angst and his rather bleak outlook.)
I don’t think I’d call it ‘twisted;’ I’m not sure what you’re getting at there. Sad, certainly; it reminds me of nothing so much as two sick kids meeting in a hospital ward. I think that the story provides an opportunity to examine the theme of identity that would have been the central idea of Mewtwo Strikes Back if only the battles and the weird self-defeating ‘violence is wrong’ message hadn’t gotten in the way. Poor Ambertwo seems to have all of the original Amber’s memories, so she theoretically has to deal with one of the same questions Mewtwo asks – “Am I Amber, or just Amber’s shadow?” – but her own childish innocence makes it a non-issue for her; although she insists that she’s Amber on the inside, she doesn’t really think the question matters and is happy just to be alive. I think that in the end, after all the chaos and destruction of Mewtwo Strikes Back, Mewtwo finally comes to see things the same way.
Pokémaniacal 