Very difficult, but very rewarding. I loved the atmosphere, the tension, and the updated homage to a long-ago classic. My only real gripe pertains to how VERY sensitive the controls are. In some rooms, such as the one in which there are monsters jutting out of the walls, it takes very precise movements to make it through the corridors alive, sometimes. Beyond that though, very satisfying once I finally worked out all of the puzzles. Bravo!