Certainly a scary and somewhat intriguing artwork. Firstly, the perfect placement of shadows and lighting. I see that you have perfectly mastered it and therefore knew how to place them. This great placement of light and shadows makes the picture much more realistic. You even managed to put some green light on the man's body to give the sense of the light illuminating in front of him. Well done!
Overall, the piece is a bit too dark, but it doesn't really distract from the main subject: the man. I've seen some pieces of artworks similar to this, and in some situations, the artist lacks the most important part: the subject is affected by the environment. That means the colors, the shadows, etc. needs to match with the environment they're standing in, therefore creating this feeling that the main subject is a part of the artwork. For this one, however, I must give you full marks, for your clear understanding of how the subject is affected by the surroundings. It creates this perfect sense of the man actually standing in the environment, rather than someone that's been hastily cropped and put into the artwork without even bothering fixing, changing, etc.
Finally, a great piece of work, good balance and contrast. The only problem I have is the lighting in some areas, but well done!