Technology enables the special effects team to create scary, believable horror scenes.
His transformation into sand and passage through a keyhole enforces the mummy's power. Inside the tomb, insects seethe, almost as if the vile creatures were to traverse the screen and cascade into the theater at any time. On the other hand, not nearly enough time was spent on the actual details of Egypt. Other than the actors stating they're in Egypt, the filmmakers didn't really illustrate it. It's practically left to the viewer to assume the location of the scene.