False advertising, over here is called Fraudulent Misrepresentation, can be taken to court over. Maybe I should take Beth/ZeniMax to court if their trailers lie to me?
Plenty of game makers lie to you. The only difference being that rather than blatantly lying, they merely stretch the truth.
Look at the Halo 3 trailers as a prime example. The diorama trailer evoked feelings of a great battle. Though the ad never SPECIFIED that such a battle would take place in-game, it hinted at it (Master Chief was in the battle, and he saved humanity, so it's perfect game material). A lot of people got hyped up over that one scene, bought Halo 3, and then were disappointed to find that such a scene was not in the game.
Stretching the truth =/= lying
Many videogame developers will stretch the truth to make their product more appealing, hence why you shouldn't trust the trailers that Bethesda/Zenimax are showing you of the Creation engine. They could be completely different renders meant to show how well the engine CAN perform, should it be maxed out, but not how well the engine CURRENTLY performs.