For me the most impressive „shadow moment“ happened while playing GTA IV. I ha a quite beefy gaming PC and the real time shadows cast from the beams of the player vehicle were generally great.

The moment that’s still stuck with me happened while stealing a car in a back alley at night. Right as my player character entered the car a police man came around the corner. He „saw“ me stealing the car and pulled his gun right when the headlights of the car turned on and cast a huge shadow of the police man in motion onto a nearby wall.