"Shadows are especially impressive—they're all real-time, based on the actual models. If you reload a weapon in front of a light source, you'll see your shadow do the same. As you move, so does the shadow—and this is especially freaky when you're looking for any movement in the room anyway. Hanging or swinging lights will play further havoc on the room's illumination and the player's shadow. It's a distraction, but a fun one.

The level of detail is simply insane. Remember those screens from a few months ago that looked too good to be true? They're true, and they move. This is mostly due to John Carmack's latest engine, which enables all kinds of new interactions and special effects."