Yeah, and Batman hasn't done anything fucking incredible? Fact of the matter is that Bullseye has an incredible talent. Perhaps Batman has an equally incredible talent. Bullseye shouldn't be able to score a fatal hit on Batman because it's what Batman does; not get killed.
Fuck, Bullseye shouldn't be able to hit Batman because Batman is prepared for anything. He's dodged bullets before, why not something moving as fast as a bullet? I really fail to see the big difference between the two.
After all, there is no documentation concerning Bullseye's mutant abilities. It is entirely possible that he's just as driven as Batman, albeit in a different "art", with no mutant powers whatsoever. If Batman were in the Marvel universe (he'd be better) but more importantly, the same argument for Bullseye's mutant abilities could be made for Batman's, thus negating any genetic advantage between the two.
Point being, maybe Bullseye is just a guy that has uncanny aim, through honing it as any normal human being could. On the same coin, Batman could be someone with incredible dodging ability, honing it as any normal human being could.