Blood's my first 'vintage' shooter, and I need some help with setting up the controls. Mouselook works fine for lateral looking, but when I move my mouse forward or back Caleb moves forward or back instead of looking up and down. Is there any way I can configure this? And is it possible to map mouse buttons? I'd like to have Secondary Fire on mouse 2.

Thanks, helped out greatly.
There's a different problem now, since I need to launch the game through Setup to use the bMouse fix, how do I play Cryptic Passage with it?

bMouse has a pass through command you can launch blood and cryptic passage with. Edit your dosbox.conf files at the bottom. Change the autoexec lines that say: Blood.exe and Cryptic.exe to read:

BMOUSE LAUNCH BLOOD.EXE
and
BMOUSE LAUNCH CRYPTIC.EXE

Addendum: GoG has updated the One Unit Whole Blood installer and has changed the way it referenced the DOSBox conf files. The [Autoexec] section can now be found in the dosboxBlood_single.conf or dosboxBlood_addon.conf (for Cryptic Passage) files.

good to hear.