Personally, I think one should not play this game with a walkthrough. This isn't a pick-a-girl type of a game, so picking different choices unlock different perspectives on the story rather than getting a different girl. Also, this is one game where bad/mediocre endings actually reveal a lot about a story. So it's not like you miss out on everything by choosing the wrong path. Using a walkthrough really takes away all the "gameplay" element to it.
Also, perhaps restrict the use of walkthrough only during the "detective scenes". And save before you do them. Some of the stuff can be quite important, so if miss something, it could screw up everything later(I use vague language here to avoid spoilers).
