having different polygons with different property...
we already have the ice and the hurt and the kill (and brutal kill) - along iwth the collision properties --- but what about 'metallic' and 'grass-like'/'dirt' and maybe ultra soft. and maybe 'cement'.
this would add versatility for realistic mode when falling. metallic and cemented polygons would hurt insanely when falling upon, grass/dirt less so, and soft ultra less.
also new sounds for bullet collisoins (and walking)

Of course the fall damage-hurting polygons will only be activated on Realistic Mode, right? Or normal?

I like the multiple collider sounds idea the best. Perhaps place different colliders altogether that are scripted to sound different .WAVs?...

Sounds good in theory, but it doesn't seem that necessary imo. Take a 30 foot fall and land on dirt, cement, or metal and there's really no difference in the end result...not enough to warrent the differentiation between polys. Unless there's a poly made of pillows, there's all going to mess you up.

I'm going more with keron, in that additional sounds seem like a better addition. Parts of a map that look "soft" could have that footstep sound associated with them, rock or harder parts a harder sound, and so on.

True, I hadn't thought about that, either; you'd then have to reprogram the current map coding, making footstep sounds an individual polygon attribute.