The symbol (famous to some, I believe, who know about Lovecraft, along with some other images I have posted like the weird hooded figure), as striking as it looks, has a lot to do with the story, you'll see... :D
I meant it's graphic ^^ It looks a little too out of place compared to the other sprites. I recommend making it smaller to fit the door, first of all. Secondly I would recommend you do some shading on it :3