The Quest/Walkthrough

Half a dozen walkthroughs for The Quest can be found on the internet. All these guides are largely incomplete: they are more or less copies of each other, and they race the player to the ending. This way, the player is left with two questions:
 * 1) How was I supposed to get the game solution?
 * 2) How about the rest of the game world?

This StrategyWiki walkthrough, therefore, shows how you were supposed to get to the game solution by yourself, as well as all the possible options.