i disagree. the star & jolly roger are what sets this apart from being jus another mecha-anime-line-art-creature shirt (which are entirely overpresent on this site, despite the fact that they usually look cool). nice job!
the skull just looks placed... like you finished the illustration. then rasterized in photoshop and then put the skull there. It is a good idea, but in my opinion it isn't cohesive with the rest of the design.
there isn't an ounce of halftone in this design, all edges are 100% crisp but i must admit the skull does have a feathered appearance. i think it's because i left a tiny sliver of space between the light gray colour of the stripes and the black of the skull. if you look closely you can see what i'm talking about.
thanks again all, all comments are much appreciated.