“This will get gross,” says a character early in the season premiere of “Westworld,” set to air Sunday, as he slices open the scalp of an android and pulls out the computer nodule that serves as its brain.

The quip may serve as a warning to viewers about what is to come in the HBO series, which during its first season established a more-is-more approach to violence and a plot that kept its audience guessing till the end.

Adapted...