Your heartbeat quickens as you watch your video game avatar run through the twisting corridors of the castle. There is still treasure to be found and a hostage to be rescued, and time is running out. Suddenly, a large shadow looms on the dim candlelit stone walls, followed by a low roar that sounds awfully close. You take a deep breath, clutch your mace a bit tighter, and ready yourself to attack. You swing around the corner, weapon raised, and…