[DruGzOG]

Originally Posted by fysiks bz2 files were only implemented in Source. Unless they added the utilities to GoldSrc in the last major update, it's not possible to use them with HLDS games.

I know Alfred mentioned it somewhere, just don't remember where.

[Powerlord]

Originally Posted by ConnorMcLeod i think alfred said bz2 is working.

Originally Posted by alfred-valve gzip downloads, not bzip2.

Source

...and even then, it won't pick up .gz files. It only works if your webserver is set up to serve .bsp files as compressed files (using Apache's mod_deflate with SetOutputFilter DEFLATE, nginx's ngx_http_gzip_module with gzip on, etc...)