10 Iconic Star Wars Things That Only Came After A New Hope
4. The Power Of The Dark Side
We've already established Darth Vader is a true sci-fi icon, but besides the red lightsaber and force choke ability, not a lot of the Dark Side is seen in the original film.
In the original trilogy's finale, we finally properly meet Emperor Palpatine. When Luke is brought before him we see him try to pull the young Jedi to the Dark Side, as Palpatine did with his father. When this fails he uses his force lightning against Skywalker, a *shocking* ability which we had not seen before.
As this was the finale of the trilogy and we had no idea how this would end, there was a genuine chance Luke could have turned.
Also, as mentioned, in the finale to the prequel trilogy, we see the full power of the Dark Side as Anakin Skywalker falls and becomes Darth Vader.