If you aren't aimed specifically at game concept art, what are you trying to do with your art? Do you have a website portfolio?
In the game industry, only sticking to traditional mediums will only hurt your chances of getting noticed. It is rare to find professional game concept artists who do not use photoshop for painting at least some of the time.
If you are just looking to turn these ideas into a game, your best bet would be to get a mod started with some other people. If you are looking to get your concepts into a professionally developed game, you would need to build a reputation and portfolio as a good game concept artist first. This would entail drawing many game related concepts outside of the horror genre, getting a game concept job, and then gaining a lot of experience in the field.
You could possibly get your art into a game without ever entering the game industry, but you would still need to be an established artist with a really good reputation, and probably gallery showings or well known illustration work in other industries.