Good idea. The rain and thunder sounds are quite good. I had to make sound fx for games myself, so I know how hard it is to record it. Good job. I like the other effects as well. Very haunting. I understand the idea behind the bass and the choir. Gives a nice spooky effect. However, they are rather repetitive. They also sound too clean and standard. I would dirty them up, make them sound fuller, more varied and interesting. The piano is actually a nice and necessary touch over it, but even that gets repetitive over time. It could do with more reverb. The song itself can do with more variation, more instruments, and a fuller more interesting sound. But you're on the right track. Just keep at it.