Here is the alien5.bsp file which was corrupted in alien.zip
just unzip it and put it into the quake2/baseq2/map directory.
then to play from the start type map alien4 at the console (U do hav the other files, Right?).
If not they are at ftp://ftp.cdrom.com/pub/quake2/incoming/aliens.zip .
Sorry for any hassles. I hate it when I download corrupt files!
Scott Kraus
Sftshldr