I really dont like anything with dribbling blood and weapons (just how I am ) so I would not buy this. That said, I like the concept, the box, the birds, the simplicity. I would typically give this a 0 ( again because of the slaughter theme)but exceptionally I will do 3.
boxy designs are a bit too easy in my view. with boxes you don't have to worry about how the image will really work on a shirt because it's got it's own composition within the box and it just looks pasted on.
in this case i really dislike the box because it doesn't seem to add anything to your concept.
Make it bigger or perhaps build more design on the outside of the box, like, I don't know, black roots growing beneath the box or something, so that you actually use up most of the shirt.
About my design