There's a game I used to love on here that I just can't seem to find anymore. It was something of a stealth game, with the only equipment your character had being a pistol and a grapple gun. You were a cop (I think) trying to take down some sort of criminal syndicate, and the graphical style was primarily just Black and White with red thrown in for blood when you were shot (if I remember correctly).
I also think that the name was a single word, and that the game was viewed from the side, but wasn't exactly a sidescroller as the levels were designed more vertically (with you trying to move through a tall building) than horizontally.
I think the game you are looking for is the one called Triggerman! I is not black and white, but dark colored and the agent that is held captive needs to escape with the use of a pistol and a grappling hook, making his way through a vertical building to escape and ultimately bring the bad guys to justice. =)
