Lord Haseo said:
All Luke did with the exception of shooting a few Storm Troopers and blowing up Tie Fighters was a brief practice session with that droid. Going from that to blowing up the Death Star is pretty jarring.

But he didn’t kick Vader’s ass. He didn’t overcome Vader’s force powers. There was nothing inconsistent in the original Star Wars film as far as the ending goes.

90% of the story was spent building up Luke’s character. He was just a farm boy nobody. He gets thrown into a wall in the Cantina. He gets blasted by the bot over and over again. He’s a whiner.

Then suddenly, he uses The Force for the first time, and he blocks the blaster bolts. Then he’s daring and brave and courageous rescuing Leia in the Death Star. Then he’s shooting down storm troopers. Then he’s blowing up TIE fighters aboard the Falcon.

Finally, at the end, he pilots his X-wing into the Death Star trench. He would have been killed by Vader had Han not come back and saved him. That bought Luke just enough time to get off his shot.