This was hands down my favourite game as a kid, and I sincerely hope it returns from the dead one day to haunt a new generation of players, whether as a remake or a sequel (hopefully the latter). You could think of Ghost Master as a reverse-SIMS game, where the goal is to scare away all the mortals inhabiting a set location. The graphics and environments, in particular, are reminiscent of a SIMS game. As the GM, you are charged with ordering around a set of ghosts to use 'powers' to terrify the mortals. As you go through the story, you are also able to 'free' extra ghosts from predicaments such as being bound to a location or trapped by a mortal. As the story progresses, you purge the town of "Gravenville" of more and more mortals, resulting in a response from the "Ghostbreakers", and more besides. It's an incredible amount of fun, though the mortal AI can sometimes make some haunting last a little while.
Overall, it's a game I'd recommend to anyone, and one I replay every Hallowe'en.