Valve has delayed the launch of its Steam Machine video games PCs until next year at the earliest.
The US-based firm said it needed more time to work on the system's controllers, which feature two haptic-feedback trackpads.
The announcement is also likely to impact the 14 third-party manufacturers planning to sell their own Steam Machine hardware.
However, one industry watcher suggested Valve had taken the right decision.
"It is targeting a very demanding demographic with the Steam Machine platform, and the controller is one of the key features designed to address the impression that PC gaming can be slightly inaccessible," said Ed Barton, a gaming analyst at consultants Ovum.
"It's a very ambitious concept to try to replicate the accuracy of a mouse input with the controller's two circular touchpads - and if it doesn't work, the platform would likely struggle to get off the ground."
Valve is best known for developing games including Half Life, Dota 2 and Left 4 Dead, as well as having created Steam, a service that includes the bestselling marketplace for PC games and contains vibrant community forums.
The company, based in Bellevue, Washington state, announced last September that it also intended to create its own games-focused Linux-based operating system, called SteamOS, in addition to a few hundred prototype machines to test it on.
It said the machine was intended to be plugged into a TV and used with its new controller that would provide vibration feedback to deliver "in-game information about speed, boundaries, thresholds, textures, action confirmations, or any other events about which game designers want players to be aware".
The idea, it said, was to take PC gaming into the living room in 2014 - a place previously dominated by consoles from Sony, Microsoft and Nintendo. Others would ultimately make the machines sold to the public.
However, a blog by developer Eric Hope has now asked consumers to be patient while the firm continued to work on the project.
"We're now using wireless prototype controllers to conduct live playtests, with everyone from industry professionals to die-hard gamers to casual gamers," he wrote.
"It's generating a ton of useful feedback, and it means we'll be able to make the controller a lot better.
"Of course, it's also keeping us pretty busy making all those improvements. Realistically, we're now looking at a release window of 2015, not 2014."
The blog refers to delays to "our in-development Steam Machines", but it appears that third-party Steam Machines will also be postponed until the controller is available.
Several of the companies involved had already announced provisional specifications, including the amounts of memory, types of processor and prices they intended to charge.
"We support the mindset to launch Steam Machine with the best possible experience," Kevin Wasielewski, chief executive of Origin PC, one of the manufacturers involved, told the BBC.
"Unfortunately that means no Steam Machine in 2014."
Anton Nilsson, purchasing manager at Swedish PC-maker Webhallen added: "Our plans for Steam Machines will of course also be pushed to a later date... We also think that the controller could use some more work so we're happy to hear that Valve is spending even more time perfecting it."
There are currently 474 Linux-compatible games available on the Steam platform, and there had been an expectation that Valve would announce further high-profile titles to coincide with the launch.
Mr Barton said the delay could make that tally seem less impressive.
"If the Steam Machines were coming out at the end of 2014 you could argue they would have a significant advantage over the PlayStation 4, Xbox One and Wii U in terms of the sheer number of games that would be available," he said.
"Coming out a year later not only means more of those consoles will have been sold, but also presumably that they will have more exclusives and cheaper games available to them.
"But Valve would argue that it needs to get its hardware right or it wouldn't be competitive anyway."
However, the news does appear to have frustrated some potential buyers.
"I agree that if they need more time to get a finished product, they should indeed take it, but going from early 2014 to mid 2014 to Q4 2014 and then to 2015?" wrote one gamer on Valve's Steam Universe forum.
"I've been a PC gamer for about nine years and I'm a fan of gaming in the living room, replaceable parts, high-end specs, so the notion of a PC console is exciting, but I literally would've bought a console for my entertainment area instead if I knew the timeline would just be constantly delayed."