When the survivors are progressing through a map in versus, the game announces when the survivors are 25%, 50%, and 75% complete through the map.
Would anyone be interested in writing a small plugin that will make this announcement appear in Co-op, Realism, and Mutation game modes?
I did some searching on how to achieve this, and it looks like it'd have to be done by using l4d2_direct. I've attempted to create this plugin using that, but to no avail.