Enjoy, I saved this post for a time closer to halloween! If you're in a mood for short horror flash games, check out Exmortis 1 & Exmortis 2. They are abandoned houses photos incorporated into a mostly point-click sequence game. Just click on my links and go to 'Play this Game' on the pages. If you ever get stuck, there's a walkthrough around as well, just google it!
For a longer halloween game, maybe you can try 'Phantasmagoria' which was released in 1995, I loved it as a kid. You do alot of exploring and watch alot of movieclips within the game as well, but the graphics will seem much low-tech and low-res compared to present day graphics. I recalled it came in a 7-CDrom set back then.