Hey here. Danny from GameSpot here. I just watched this and went to our video files team to see what the story is. According to them we were sent this video, along with 2 others (1 was this gameplay with commentary) was sent to us by somebody associated with the game (Dev/PR) as an asset to be published on the site. After processing it through our video robot (which also publishes to our YouTube channel) the video team decided to pull it as it seems like it was just random gameplay (and honestly, it's that interesting for our audience). So it never reached the site. Unfortunately our YouTube guy didn't know we weren't going to put it live and so it made it to YouTube. It was subsequently made private I believe.
As for the other Let's Play, that was straight-up sent to us by the developer in a PR email. We produce dozens of trailers for developers around the world and don't have time to vet each of them - if the developers are sending us footage of their games, and they are the ultimate owners of that footage and property, then we take that as enough proof that it's something they created. In honestly, how else are we to know who the person is who's talking.
I apologize if it looks like we're stealing your bread and butter, but this is an issue between you and the game creators. From the sounds of our files team this is something rare, but it does happen. If you're still pissed I'd recommend getting in contact with the games creator to ensure they don't do this anymore. Our video is no longer live so it shouldn't impact your revenue. But we don't go around stealing random YouTubers videos. We have a team of people who capture gameplay of games when developers don't send us assets. Not only would it be terrible PR, but ultimately these videos don't do the type of traffic we desire. I mean GTA V and Mortal Kombat X came out this week - our users aren't particularly fervent about Combat Arms.
Hope this helps clear is up.