In 2006 and 2007, Valve and Taito released an arcade version of Half-Life 2, with all sorts of strange and fascinating resources.
In 2013, it was finally dumped and coaxed into working on normal PCs, letting people get at the resources involved.
This pack contains most, if not all, of the new stuff - maps, models, sounds... - set up to work in Source Filmmaker with minimal fuss. Because let's face it - everyone needed HL2 characters with afros, devil horns and fish heads.
Here's a video by Marphy Black demonstrating all the characters present in this pack: https://www.youtube.com/watch?v=i0yiyZfF9o4