You must guide Hector through rooms of increasing difficulty in order to save all the souls, collecting keys, dodging spooky-yet-adorable monsters and solving puzzles in order to make it through unscathed. One thing I really like about the series is that each chapter integrates new elements in order to keep the game-playing experience fresh; for example, the Orange Library adds mysterious portals that zip you to different parts of the chamber, the Yellow Tower adds cursed, non-crossable floors, and so on.

Analysis: Phantom Mansion is a great example of casual gaming in its purest, most entertaining form. I found the puzzles to be challenging but not confounding, perfect for a lazy afternoon or five minute coffee break. The game also does a nice job of introducing the elements gradually so as to not overwhelm the player. By the time the most difficult levels are reached the mechanics are almost second nature. The (admittedly superficial) story adds a bit of depth, and the adorably creepy graphics and score are irresistible.
Website
http://www.gimme5games.com/index.jsp?id=pm_blue
Review from here
http://jayisgames.com/archives/2008/01/phantom_mansion_spectrum_of_souls.php