That's going to be interesting litigation. There's a legal analysis under UK law here.[1] It's not too helpful. WIPO suggests that legislation may be desirable to give game developers control over videos of games.[2] Their country-by-country analysis is all over the place.

It's a tough call. Arguably, the player is the performance, against the game as a backdrop. That could be argued as a transformative use. If you make a video of someone playing golf on a Robert Trent Jones golf course, Robert Trent Jones (or his estate) doesn't get royalties. If you make videos of people playing sports with sports gear with prominent logos, that doesn't mean the sports gear company has a copyright interest. You don't have to pay royalties to car companies when their cars appear in a video.

Cut scenes may be an issue, since the player isn't controlling them.

[1] http://www.develop-online.net/analysis/uploading-gameplay-co... [2] http://www.wipo.int/export/sites/www/copyright/en/creative_i...