I think it's a really badass design. The face particularly, showing so much bad-assery and a vivid expression, really good to look at. Are you planning on tattooing it, or is it only for portfolio-use?
With tattoos I would most likely assume more vector like images instead of such a dynamic pop out look. I mean its a tattoo, as far as trying to make the painting look like it jumps out at you, I don't think its that implied, but not really my department so I'm not sure. And there's some comments up there about this dude looking like bruce from finding nemo, but for some darn reason I can't stop thinking about this one cartoon show I use to watch as a kid about these mutant grungy sharks that fights crime, sorta like TMNT but with sharks. Hell I don't know I probably dreamt the whole thing up. Well at any rate this look like a pretty good anda pic if you know your audience, so real good job.