Kill as many waves of enemies as you can, with friends online or take fight alone.
Changes since 0.1.8: -Headcrabs have joined the zombie wave, looking for some victims to zombify. -Fixes for maps contingency_bunker, contingency_factory, contingency_lockdown, contingency_overpass and contingency_ravine by MyCbEH (Musien) who added headcrab spawn flags and force field hum/buzz. -Default server settings now have zombie wave multiplier 1.5 instead of 1 accounting for spawning headcrabs as well as zombies. -Fixed an oversight in the rendering code that may have caused a bug.