The Space Quest series has been a long time favorite of mine. Just this past summer I played through all of the games and really enjoyed them. These games have stood the test of time. Their gameplay is slow and antiquated but they are still full of comedic gems and a great storyline. I'm surprised to see that GOG has released episodes 4,5, and 6 first before episodes 1,2, and 3. They are all worth playing through. But, I would have to say that episodes 4 and 5 are the best of the series. Still, I just don't think someone could appreciate the main character, Roger Wilco, without having played at least episode 1.
If someone is considering buying this game and hasn't played any of them yet I recommend using a walkthrough from time to time. If you want to try to make it through without one that is great. It's definitely possible, I did it as a kid. But, since the gameplay is rather old I can see someone becoming disinterested if they became stuck at some point in the game. That is why I say just play through the game as a leisurely pace and consult a walkthrough after you are stuck for a while. That way you can finish the games and enjoy the storyline and humor. The only caveat to this is that you should save your game often and definitely try to kill yourself as often as possible. The possibilities of death are some of the most humorous parts of the game.
Enjoy these games and appreciate them for what they are.... classic adventure gaming!