Hmmm, the amount of blood that sticks to the walls doesn't seem like a lot, so I'll asume you're talking about the blood decal coming directly off the entities.
To tone that down you can simply make a new Blood decal, the current one can be found at the following path:
FPS Creator/Files/gamecore/decals/blood
All you gotta do is alter that one, or make your own (as long as it fits within the guidelines for decals) then replace that one with it.
The one and only,
~PlystirE~
Dammit, Jim! I'm a programmer not a graphic designer!!!
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