I don't know if it will work or not, but whenever a movie is billed as being "Christian" there seems to be a built in audience already. Not much of one, but I do know Christians that will go and see anything billed in such a way.
There are many horrific elements in the Bible, that lends itself to a good horror story told well. In the Old Testament at least. I'm still waiting for that story.
Speaking of the Bible and it's horrific elements, I do get irritated at times when a secular story is told using those elements. Not that I'm religious or anything, but The Exorcist is a prime example of the problem I have. In a film in which it's a given that demons exist, I get so tired of God's servants being so helpless. We're supposed to accept that there's a devil and there are demons within the context of that movie, but we're also supposed to accept the fact that the representatives of God on earth are powerless to do anything as well? There's always an excuse such as the priest having a crisis of faith, but when confronted by the devil's handiwork in person, you'd think the priest would at that time say to himself: "Well, if there is a devil, God must exist, now let's kick some demon butt." (Supernatural, Dean, I'm looking at you. How long did it take for you to accept the possibility that angels exist? In a world in which he knows demons and hell exist, it takes him way too long to even consider the possibility, much less accept it. Irritating.)
And don't even get me started on ghost stories. Within horror, ghost stories are my second favorite genre, but I do have issues with most of them. This is way off topic, maybe I'll start a new one.
As for this movie, it seems to have an uplifting ending. So maybe redemption is at hand. A common theme in many stories. Christian and non Christian alike. Based on that teaser, I certainly wouldn't go out of my way to see the movie. There was really no narrative, just a series of bizarre random images. Maybe the trailer will do a better job of selling it to me.
Oh, and I liked Stryper! To hell with the Devil! 
