I thought Vader was semi-lying. OWK mentioned clones wars and such. It made sense to me that DV was a clone of AS (and therefore evil of course). DV killed AS,etc. So biologically DV was sort of correct. (Hence Luke wasn’t able to detect a bold lie.)
So Ep. VI was set up to be really great with a counter-revelation and all that. Blyeah. What a let down. I’m glad no other Real Star Wars films were made.
Considering the film came out before I was even born, I had heard about it well before I actually saw it.
I saw it upon its release in 1980. I was 13 at the time, and as I stated above, I was figuring it to be a lie to manipulate Luke. My thinking was clouded by the fact that Vader was able to contact Luke via the force while on the Falcon and Vader was on the command ship. He even calls him “father” during that sequence. However, at that point, the whole Star Wars phenomenon was only 3 years old and we still didn’t know how the force worked or if people’'s minds could be manipulated like that (“Search your feelings, you know this to be true.”). So, my conclusion was that it was a lie. Again, why would a guardian of the republic, a Jedi (Obi-Wan) lie to or mislead Luke? It just didn’t jibe with my ideas of the light side of the force, so Vader HAD to be lying in my mind. In retrospect, I think the best explanation is this: Lucas wanted to make a huge story, he got the chance to make Star Wars and made it as self-contained as possible in case he’d never get to make anything else. When he did get the chance to make more, he had to shoe-horn in and retrofit ideas that he originally had. Sometimes it worked, sometimes it seemed forced.
Luke: "No… That can’t be… That’s impossible!"
Me: “Umm… Yeah, it’s pretty much impossible.”
Me: (several viewings later) “Hmmm… nope, still not buying it. Definitely impossible… isn’t it?”
Me: (after still more viewings) “Well… If not literally impossible, at the very least it’s ridiculously implausible… seeing as Luke only got involved in the first place because the droids crashed near his house. And how could Luke get his father’s lightsaber from Ben, if Darth Vader is Luke’s father, and already has his own lightsaber? It’s as laughably unlikely as… as if Leia turned out to be Luke’s sister! Or Darth Vader had built C-3P0! Or Yoda and Chewbacca were old pals!”*
The ‘two lightsabers’ argument was really the clincher in my young mind. For some reason, it never really occurred to me that a Jedi could possibly own more than one lightsaber. On the other hand, even at that age I instinctively knew that when a character cries out melodramatically that something “can’t be,” the thing being denied is automatically an ironclad certainty.
*I maintain that my original reaction would have been expressed in these terms. Unfortunately however, the technology to realize these comparisons did not exist at that time.
I was 6. I don’t recall my reaction. I agree with others that I was much more horrified by the hand-cutting-off and by Han Solo being frozen in carbonite.
I saw the movie with my older brother and sister, I think. I was 10. I don’t remember my reaction, I just remember that when I got home my mom asked how I liked the movie, and then asked, “So is Darth Vader really Luke’s father?”
She knew, but she took care not to spoil it for me. Sometimes my mom can be pretty cool after all 
I was about 14 and believed every word of it. And I was horrified and delighted - my Luke-loving soul felt terrible empathy with him, but the nascent storyteller within me thought, “oh, what an awesome way to make a hero miserable and his story more complicated!”
But the part that really freaked me out wasn’t that, or even Luke’s hand getting cut off. It was when he’s hanging for dear life on the edge of an abyss while Vader’s all “come with me to the Dark Side,” and Luke has nowhere to go but up if he wants to survive, and we’re all thinking “oh he’ll jump up and start fighting again somehow,” and then Luke just looks his dad in the helmety eyes and he lets go. He fucking LETS GO! Talk about a badass good guy. I screamed louder than Luke does on the craptastic redone version where Lucas makes him sound like a wuss.
Loves me some Luke Skywalker. I know it’s cooler to like Han, but so be it.
You’re right! That’s what made the scene perfect. Luke is given a “offer he can’t refuse,” and he refuses it. Luke is cool, I agree, and that was a terrifically cool move.
I liked Vader’s reaction, too; the way his outstretched hand just kind of droops.
“Crap… I wasn’t expecting that.”
I guess this is appropriate: The Robot Chicken version.
I saw ESB before SW, so I didn’t have much invested in the characters; and I saw that ESB was setting up some hidden connection between the two of them, so I wasn’t all that surprised.
Now my baby sister–she’s another story. She never saw the movies until she wsa an adult (she’s 32 now) and saw them one after the other about 10 years ago, around Christmas, when she was sick and I was taking care of her. (USA network was playing the trilogy in sequence.) Somehow she’d managed to remain utterly virginal about the Lucas mythology, and between that and being semi-delirious with the flu and her medications, she got really into it. Thus, Vader’s big revelation hit her really hard.
It was very, very funny to watch her reaction, actually.
If you’re not going to take this seriously, I’m going to my trailer. 
Me too. I thought he was lying.
I saw it on video when I was about nine or ten. Not too long after that, I got to see RotJ in the theater. I vaguely remember seeing SW when I was very, very little. I woke up in the back seat of the car when we were at the drive-in. That’s one of my earliest memories.
I’ll echo what a lot of others said, in that Luke’s hand getting cut off and his choosing death by jumping into the ventilation shaft over conversion to the Dark Side was even more shocking than Vader’s statement. At that point, I thought Vader was just screwing with his mind. Of course, that little theory got shot down when Luke was lying down in the Millennium Falcon with a pressure cuff on his stump doing the whole telepathy thing with dear old dad.
I will argue that Leia and Luke’s relationship is foreshadowed in ESB, for certain, and the bickering in SW is not much different from the usual ribbing a sibling gets. There’s usually only one prophesied birth of a savior in the heroic cycle, and having the “other” be a twin keeps your prophesy from being less useful than a newspaper horoscope. It did feel way wrong by that point though. She should have been singled out for training or something before that, not just some foreshadowing in the previous movie with some half-assed ambiguous references in the first one, and no build up to a reveal that doesn’t happen until about 3/4 of the way through Jedi.
And, shit, Ben, throw the kid a warning that he’s been playing tonsil-hockey with his long-lost sister for Force’s sake. What do you want to do, mess up his sex life permanently when he finds out? He was probably already beating off to imagined scenes between the two of them by that time. I mean, she is a princess that he rescued. If he were a little older (and less whiny) he would have swept her off her feet and right into bed. That’s the usual hot princess reward for the heroes who deliver them from evil. So not only does poor Luke not get any Leia booty, he also gets some serious squick from imagining the two of them doing the nasty while he’s “waxing his wookie” over the last couple of years, all because Obi Wan likes to omit vital information and tell stories “from a certain point of view.”
[hijack]I generally don’t participate in these threads much. I am a SW fan. Haven’t kept up with the EU since before the prequels started coming out, but I still love it.
I think the series is cinematic gold. It may not seem like it to a lot of people now, but even gold can be picked apart until nothing’s left. Which is why I don’t participate in these discussions. SW works if you just ride along and enjoy the moment, the sheer impact of the work. Analyzing space opera never works; it’ll just end up looking like garbage, no matter how good it may really be.[/hijack]
Anyway, I was born the year RotJ came out. Specifically, I was another in utero RotJ watcher. 
I can’t really comment one way or another to the OP, because I grew up with the old trilogy on VHS. It was ingrained in me the way religion is ingrained into the children of a faithful household. I knew the whole story as far back as I can remember. I was also the envy of all my friends as a little tyke because I inherited my brother’s considerable Star Wars toy collection, this during the decade (or so) before the special editions came out and they started making new ones, so no one else my age had them.
I’d just like to point out here that those of you who thought it would turn out to be a lie, you’re not alone. When shooting, no one knew about the lines (Prowse, the body of Vader, had been given some random filler line to say to help keep the secret). Kirschner (the director) knew, and told Hamill the day of shooting. Jones was only let in on it the day he recorded the lines, and has said in interviews that he too was sure that Vader was lying!