Just from an artistic standpoint, there seems to be many different light sources. The top of the dynamite should be more of an oval rather than a football. The skull itself is "squished". These may be things that were done intentional though, I don't really know. I'm pretty dumb when it comes to traditional-style tattooing. But those are a few things that stood out to me. Also, the broken linework everywhere. I would decide if you want to have a line, or create the illusion of a line with shading, and stick to it for that area, rather than having a bunch of broken lines, especially with the teeth. But again, that's just personal preference and I'm too biased towards realism to speak for tradition pieces. This probably does you no good.
