Well? Comparing it to other NES titles (Ninja Gaiden, Zanac) 
How difficult is the game? Might I be able to beat it? 
 
I'm thinking of getting it on the VC.

It's definitely got that level of unfair difficulty. You only have one life, your weapon sucks, the jumping is floaty to the point that you will die a lot because of it and the levels are designed in such a way as to be infuriating. But of course if that's what you're looking for than go for it. You will only be $5 poorer.

Well, imagine like...  being sodomized by an antique hunting rifle. And then they fire the antique hunting rifle, so now you've been shot (through the ass, mind you) with a lead ball, and there's gunpowder coating the inside of your rectum, and you've probably got some kind of bowel movement byproduct mixed in with your wounds, so now you've got a systemic infection, and you're almost assuredly going to die.
 
It's a little more hard and unfair than that.

Easily one of the hardest games on NES.  It's one tough cookie.  Compared to Ninja Gaiden, maybe around the same difficulty or a little harder.

it's about on the same level as ninja gaiden, maybe not THAT hard 
 
if you gave it a long time you could probably beat it.  but it won't be easy 
oh and be prepared to write down really long passwords.

The difficulty is absolutely ridiculous.  There is a password feature, thankfully, but that's about the only mercy that the game grants.