Having provided me with hours of fun, I just had to draw attention to this wonderful game. Especially since it's free.
The game came out in the 80's, and it is primarily a puzzle game, but layered and rich enough to be different from just doing plain puzzles.
It is a story loosely based on a Tarot deck, and tells of a wandering Fool looking for 14 treasures. As each step of the way is solved, you get a piece of a map. There are 80 map pieces, and that is a puzzle in itself - to put them in the right order. Once the map is solved, you have to use the clues in it and the story to find the 14 treasures.
The puzzles are varied - crosswords, anagrams decryption, find-aword, jigsaws, etc. There were a few that relied on tracing a path with the mouse, and they require a steady hand. Many of the puzzles come with instructions, but a few don't, so that working out what to do is part of the fun.
I played the game on my XP and followed the instructions from the developer's site. I had to download the emulator, but everything went smoothly. It played in a small window, and without color, but that didn't detract from my enjoyment. There is a glitch at the end when you solve the map, but the developer thoughtfully provided a saved game to allow you to continue.
I suppose you could classify this as a casual game. I played it a few hours here and there over 1 month or so. I have since downloaded the available other 2 games - At The Carnival and 3 in 3. His website announces a sequel to Fool's Errand called The Fool and His Money. I'm not sure how current it is, but I'll be looking forward to it and will gladly purchase it when it's released.
You can find the game here: The Fool's Errand