The official reveal is scheduled for their April issue (#97) and they had this to say regarding the matter (translated from Norwegian).
In our April issue we will offer a scorching world exclusive where we first started going to show pictures and talk about the sequel that is guaranteed to make you sweat.
Other than that, no other details has been shared – although GameReactor shared that the game isn’t one that’s already been announced.
While we have no idea what it is, possible signs point to a Half-Life 3 reveal -yes, that Half-Life 3! The reason for this is a commenter on the mag’s site stated that he wouldn’t be interested in any announcements if it wasn’t Valve’s Half-Life 3; and to this the magazine answered, ” he should be excited.”
We’ll update the news as more info becomes available.