Not all that impressive for a game today, but this was basically unheard of in the 1980s and it explains how the movements were so smooth.
If you’ve played it a decent amount of times, you will recognize every movement in the live action video as it looks in the game.
Also, for those who don’t know what rotoscoping is: https://en.wikipedia.org/wiki/Rotoscoping
Some of the original footage is on Youtube, and you can tell which of the takes of the ending princess hug scene made it into the game because of how she swings a foot back.