>>723700781
>by killing approximately 2 billion mutants.
Mutants aren't killed. Its not even stated if he kills the absolutely insane ones or tries to just hold them until they fix themselves. The 25% of the world pop was the total world pop and was from the event in totality, not just sam.
>Like to think that only 2 billion looked outside is kinda ridiculous
Eh, i'm iffy on it. Putting aside the prior point, if you luck into an overcast day and then hear some severe weather report plus internet talk saying some weird shit is going down you'll probably keep your head inside. People could record other Cursed. And not all cursed died nor count as effectively dead through insanity/evil, plenty will continue to be citizens as seen from the ending montage. Plenty of the casualty count comes from regular people who died as a result of the social breakdown/cursed, shit like hellcar eating people.
>Sam fixes everything
>You didn't do everything but you were a big help
Part of the game's themes is taking the risk of extending compassion even in the direst circumstances, of always trying to connect with others even if its hard, though not checking too deep for the skeletons in the closet; it makes sense it'd have its good ending actually reward that.