In a matter of hours Valve will launch a revamp of Alien Swarm, an Unreal Tournament mod that was released back in 2004.
And the indie giant says the free game will be released along with its entire code base, as well as a number of feature updates to the Source engine and SDK.
In 2005, one year after the release of Alien Swarm, developer Black Cat pledged to build a sequel using Valve’s source engine – yet the group went quiet following the announcement.
It has now emerged that Valve hired the Black Cat team after the release of Alien Swarm, and delegated work on the Left 4 Dead and Portal series.
But the group was also intermittently working on the Alien Swarm update "in between contributions to the other Valve projects".
It is not known if Valve acquired Black Cat outright. The Alien Swarm product listing puts Valve as the title’s developer.
The string of announcements put into context Valve’s ongoing relationship with the mod community – a bipartisan model that has seen the release of ‘mod-born’ titles such as CouterStrike and Portal (a revision of Narbacular Drop).
Valve says that its new codebase release and SDK update will give developers "more insight and examples for using Steamworks in game production."