Fair call...I have never used skull imagery before..I usually do pastel/child like pop images, but tried this as a departure. I'm sure there are some skull fans out there though!
Check my other new design I'm about to post - more skulls, but see what you think.
i like this one more for sure, although yeah skulls tend to bomb on threadless. i think the imagery is cool though and can't really think of any changes to make. best of luck to you.