Well, I just finished the first episode.
A little short perhaps, and heavy on cinematics, but that's to be expected since they have to set the scene for the series.
I thought they really got the right "King's Quest" feel to the game, and the control system is nicely done.
My only criticisms are that perhaps it relies a bit on the player having knowledge of the previous KQ games. Also, there isn't much (if any) pathfinding for moving graham around, so you end up clicking a touch more than perhaps could be necessary.
Generally though, I really enjoyed it and I'll be waiting on the next ones. Kinda suprised they aren't charging for it though, if the rest of the episodes are of similar quality I'd happily pay a few quid for them.