

This. I don’t understand why murdering your alt-self is “necessary”. Wouldn’t you actually want to preserve your alternate-self at all costs, to ensure you can continue to make return trips?
The real issue here is that - if your home reality works by the same rules - once you leave it, you can never return home ever, because no alternate version of yourself exists in the one you originated from after you leave it.
Before you say “hey, that sounds awesome, this place sucks!”, consider that finding a better reality is not guaranteed.
The only problem with reading the Manga is that after you finish it, the film seems so simplistic and flat in comparison. The Manga has so much greater nuance, tragedy, and depth to it.