Sega Europe has acknowledged complaints that Aliens: Colonial Marines trailers "did not accurately reflect the final content of the game".
The publisher told the Advertising Standing Authority (via Reddit) that it 'wasn't aware' of issues regarding the final game quality when the trailers in question were produced, in some cases "several months before release".
The company will now include disclaimers on its website and in "all relevant YouTube videos" explaining that the Colonial Marines trailers depict footage of "demo versions", it said.
The ASA said in a statement: "Our role in cases such as this is to ensure that marketing material isn't likely to materially mislead the public.
"We consider that with this disclaimer in place, customers are unlikely to get the impression that the trailer shows the finished product, and the ads are therefore unlikely to mislead."
The original complaint was submitted by Reddit user 'Subpardave', who argued that the video game industry needs to be held more accountable for its advertising.
"My aim was not to get fines, compensation or any of that," he wrote. "Gearbox and Sega spoke very clearly - by saying absolutely nothing - and showed the purchasing community that they would rather this mess all quietly disappear."