This is what Amnesia developer Frictional Games has charged Dear Esther's thechineseroom with accomplishing in Amnesia: A Machine for Pigs.
"The thing is, if we don't frighten people as much as the original, then we've failed," Dan Pinchbeck of thechineseroom told Gamasutra. "But now we have to frighten people that know what to expect. The big design challenge is: How do we protect the things that make Amnesia great, and how do we evolve everything else to make a really fresh experience?"
Pinchbeck wants players to be reminded of the original Amnesia with each shiver of fear, but to be so enthralled by the new, horrific world that it will feel as if "something has burrowed into your head and is just scratching its nails at you. But you're so hooked. Inside, you're peeling away like bodies from a pile and you just can't stop yourself," Pinchbeck said.
Now that sounds like fun.