Any one ever play any of the Elder Scrolls series games? They are a lot of fun. Commonly they are known as "Morrowind" which is The Elder Scrolls III, and "Oblivion" which is the Elder Scrolls IV. They aren't too Halloweeny, but there are some things in the games that could be considered horrific. Like the Daedra for example are like the demons, there are walking skeletons, walking dead, and in Morrowind there's an expansion set you can get where your character can become a werewolf. In both games you can also become a vampire...although the game play is really rough because you get your life zapped going out in the daylight.
Also, you never play the same game twice, because your character becomes a unique creation by you, with a variety of races and classes, and the storyline varies by your actions. My favorite race is the Khajiit...for obvious reasons. In Morrowind I always favored the battle mage class, although making a custom class is fun as well.
Unfortunately, the last time I played Oblivion it fried my video card.

Guess my computer couldn't handle the game's awesomeness.