The gap will begin to widen between the paid and free-mod versions of Black Mesa, a Valve-sanctioned remake of Half-Life 1.
Multiplayer is already exclusive to the £14.99 Steam Early Access version released last week. Required adjustments of the game's engine mean the much-anticipated Xen levels will be, too.
"It's impossible [for the new Xen levels to be added to the free mod]," said multiplayer level designer Joe R in a Reddit Ask Me Anything. "In order to make Xen look the best it possibly can look, we need to upgrade the engine with new features. These new features will make it incompatible with the mod version."
He added: "Since the paid version is on a newer engine, we aren't able to back-update the mod version with some of the features of the paid version. That being said, we are looking into porting bug fixes onto the mod version that are found in the paid version."
When those Xen levels will be finished - when Black Mesa will finally be finished - isn't something the Crowbar Collective team is ready to say. "We have an internal schedule that we're pretty confident we can meet. We just haven't released an official deadline/ETA to the public," added another multiplayer level designer, Jordan F.
"We've only been on Steam [Early Access] for less than a week, so it's a little too early for us to have a concrete release date."
However, the team has made one significant alteration and that's to the game's final price; it will now remain at £14.99. The Black Mesa Early Access FAQ had warned that the price "may go slightly higher" but the community didn't want that.
"Pricing was a controversial issue on the team all the way up until release," wrote Jordan F. "We worded it that way to leave our options open in the future, but given the community's reaction we've decided we're gonna keep it at $20 [£14.99].
"The price is never going to increase past $19.99 for any reason. We apologize for any confusion and misinformation about this."
In addition to the Xen levels there are "lots" of multiplayer updates planned including new modes and maps. Some single-player areas that "are looking dated" will be tarted up too.
Mac and Linux versions of Black Mesa are "in the pipeline" but there's no timeframe for release.
There are no plans for remakes of Half-Life add-ons Opposing Force or Blueshift.
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