Silent Hill strongly implies that the town is being swallowed by Alessa's nightmare, and that it's really happening. There's no multiple dimensions. The nurses and doctors are really infected and were real people. Cybill got infected by the same parasite. The town was destroyed.
Later games make it more ambiguous, and the monster designs less human.
i cant play that its too scary
I thought Alessa was involuntarily creating manifestations of her nightmare. The Lisa that Harry meets in the game doesn't understand why she hasn't become a monster, and it's because she already is one, a manifestation of Alessa's memories of the real Lisa. She remained human-like for so long because she was one of the few people who was nice to Alessa. I think she's like Marie from SH2, a manifestation of the memories of a real person, but not actually physically that same person. Disturbingly, they don't know that they're doppelgangers (see the Born from a Dream scenario).
I mean I guess there must be a parasite-like thing infecting people, too, though, since Cybill was real and turns evil.
>>383750868
>lots of theories
She's just the last one to be infected and is the last to turn. She's no different than any other nurses.
The only place in SH that isn't real is "Nowhere". That's an actual weird pocket dimension that they leave via a portal.