The way I see it, any story needs a set-up: the narrative arc has to be able to rise in the first place. If you take the first 30 pages of most novels, they will be interesting but won't necessarily be a great indicator of where the rest of the book is going. If you take the first section of Heart of Darkness or The Castle or VALIS or The Call of Cthulhu (to name whatever I happen to glance at on my bookshelf), they're certainly interesting and engaging, but shouldn't necessarily be taken as forecasts for what the rest of the book will be like. When all five episodes are done, I'm sure they'll form a shapely narrative arc of which episode 1 is only the first piece.
Also, regarding what DMD posted a few pages back:
Remember, KQ was essentially supposed to be a mish-mash of fairy tales and myths creating something original and fairy tales aren't exactly known for their emotional or character depth. Why does every character have to have a ten page long back story or psychological profile?
What happened to just having fun? What happened to simplicity?
The KQ series did start out as just mashing fairy tales together: troll bridge + dragon + beanstalk + leprechauns = KQ1. But as the series has progressed, I like to think that the storytelling has become more complex: KQ3 is darker, and Manannan is more fleshed out as a character than any of the NPCs were in KQ1 or 2. KQ4 incorporated complex ties of loyalty, to Rosella's family, to Genesta, to Edgar and even to Lolotte.
(After all, should you really be finding all these treasures for her? Giving her Pandora's Box is surely not a morally acceptable move. And Edgar is very nice to you, but is still turned down when he proposes: on the one hand, that's a bitter moment for him, because he would have been married to Rosella, against her will, had he obeyed his mother; having done the right thing, he's actually been punished. Rosella's refusal of marriage in a fairytale adventure game is also an unusual feminist statement in a world where men are the ones who must kill things and women are the ones who must marry them.)
By the time we get to KQ6, I think there's enough complexity to the plot and characters that the game has, if not broken away from the "mashing farytales" mentality, at least evolved it to such an extent that it's capable of mature and emotionally engaging scenes. The underworld section, with its confrontation against the Lord of the Dead, where the key to solving the puzzle is the realisation that Death's existence is essentially a reworking of the Lucifer story with all its eternal bitterness and envy for humankind, is one of my favourite sequences from the entire series not only because it reworks myths (Charon and a riddling gatekeeper, and even the little internal game-myth of seeing the "tickets to the underworld" sequence when you die), but also because it climaxes with an understanding of an emotionally charged sequence (the Lord of the Dead section) which is essentially the summary of the Lord's tragic arc.
Yes, King's Quest is a jumble of fairytales, but it matured beyond that into coherent and emotional storytelling. Personally, I'd rather have deeply thought out character development to fiendish puzzles; many people won't agree with me, but that's beside the point because you can have both! But to say "I want to have fun; scrap the characters" seems a bit simplistic, to me.