Hey there, everyone.
I'm a left-hand mouse user, so often my first experience with any game is going into the menus and spending a half hour re-fitting the control scheme, which was developed with a right-handed mouse user in mind. Not a huge issue, but it has become one in Blood 2. For some reason, when I press try to map "backwards" to the down arrow, it instead moves over to "turn left" and maps that to the down arrow, much to my annoyance. I've tried multiple times, and the result is always the same. I'm trying to play using the numpad now, but it is proving mildly difficult, as I'm used to having jump and duck mapped to right shift and right control respectively. Is this a Windows 7 issue, or a general problem with the game, and what can be done to correct the issue?

It's a general problem with the game. See this post.

7.
Though at this point, we're far enough to where this shouldn't be an issue for a company who's whole point is porting old games to modern systems. 7's been out long enough, to where the OS should be taken into consideration.

That may be true for the dosbox games, but Blood2 doesnt use doxbox.
Gog doesnt have the source code (as far as I know), so cant really change much with Blood2.
They can make an installer for it, have map packs and patches, and port in via cfg files lots of keyboard/mouse/monitor settings.
But they cant really fix bugs IN the game.
This is why I dual boot my gaming machine.
I have XP for old games and network games, and I have Win7 for newer games, that will take advantage of DX10 and are optimized for not needing direct access to hardware.

Well, aside from this issue, I find the game very much playable. Yeah, it crashes from time to time, but it's not that frequent, especially if I keep the resolution low. It's just this issue that miffs me, and I really wish there'd been a program included to make changes to the CFG outside of the game proper, since I'm not exactly a config wiz.
Funny enough, I have Shogo as well, which is another Lithtech game, but I don't have any of these issues. Hell, that one runs like a dream on my 7 rig.

You'll have to select "forward" and then just press the down arrow. It'll move the cursor down to "backwards" and change the key for that to down. It's a problem with the game itself.
It seems this site is littered with "Windows 7 is the problem" comments when I can get all of my games (35+ of them) to work perfectly without tinkering. This game works great on 64-bit (and 32-bit) Windows 7, even on higher resolutions.