It's frankly easy to miss. There's the original entrance that runs along the Plaza of the Stars (the main drag). The second theater's entrance is tucked on the other side of the building near the extended queue (where Asylum in Wonderland/Krampus devoted much of their queue space).
And re:
@Jwhee - yeah, that doesn't shock me. I understand many of the old props and medium-sized set pieces are still lurking in upper floor storage areas. The Vertigo stairs were obviously repurposed, but yeah, they just sort of tore out the old exhibit areas/Psycho theater and plopped a new box in there... not at all "form fitting" to the space.