Left 4 Dead 2

Left 4 Dead 2

Glubtastic 5
Why do the L4D1 survivors die when playing with 8 survivors?
I noticed whenever I play any chapter while using the 8 survivor mod, the L4D1 survivors die before even starting. I can't seem to respawn them either since they still die afterwards. The L4D2 survivors are still alive tho. I'm not sure what causes this.