Valve co-founder Gabe Newell revealed that Steam Box will reach the hands of some customers within the next three or four months.
"We're working with partners trying to nail down how fast we can make it," he told the BBC before estimating that the prototypes will be ready for shipment in less than four months.
"There are noise issues and heat issues and being able to [deal with] that while still offering a powerful enough gaming experience is the challenge in building it," Newel explained the reasons behind the hold up.
The Valve CEO then revealed that the company is looking into equipping the Steam Box gamepad with a heart-rate monitor.
"If you think of a game like Left For Dead - which was trying to put you into a sort of horror movie - if you don't change the experience of what the player is actually feeling then it stops being a horror game," he explained.
"So you need to actually be able to directly measure how aroused the player is - what their heart rate is, things like that - in order to offer them a new experience each time they play."