Out of curiosity, I checked the Infinity demo's Sounds file against the full version. Not much to write home about: all of the new sound slots are 8-bit, and a few random VacBob quotes are transposed with another in the same group for some reason. One new thing I did find though, in VacBob's first Trash Talk slot (later replaced with "I got 'im!"):
"Nasty!", he says. I wonder which hard death animation VacBob saw. Shame it's only in 8-bit.
Can't remember if the Infinity demo's been covered before, but I definitely didn't see this in the Sounds section.