The Perfect Dark engine is a modified version of that of GoldenEye 007, and many of the gameplay features are unchanged. For instance, the manual aiming system, originally inspired by Sega's Virtua Cop, is graphically enhanced but essentially the same. Players can crouch, duck and lean but notably there is still no ability to jump. Despite this, it is possible to drop from most ledges, a feature rarely used in GoldenEye 007. Most weapons have a finite magazine and must be reloaded after a certain number of shots. Interaction with the environment is via a single "Use" command, which opens doors, activates computers and so on. The engine never had an official name, its always been a upgrade from past game engines.