I have not read the review in question nor have I played the game in question, but I will comment on the situation
I watched a few video reviews on GS (of older games too), couple of days ago. Yes, I was supposed to be studying... The guy's reviews were pretty decent, I liked him more than the other reviewers and remembered his name (I don't read the names of authors of written reviews). So that's +1 for him in my book.
I have seen K&L in action and I really don't think it's a bad game. Reminded me a bit of Hitman (same developers?). It could be a 6 on a "real" 1-10 scale. But if Oblivion and Unreal get 9+ grades, I think it deserves at least 7.5 from my limited experience (I didn't play it, but the action seamed "solid" and I heard that the story is pretty interesting).
I think he brought this on himself, but the editor should have known better to publish it, if it was that big of a deal (and it seams it is). There was no need to trash the game (6.0 score is trashing by GS standards). He should have given it 7.2 (neutral) and left the tone of the review unchanged, keeping his "integrity" and his job. I mean, who would buy the game based solely on 7.2 score and a negatively toned review?
I know I'll get flamed for the above statement, but the game is somewhat innovative and I'll be sure to play it and inform The Codex of its real "value" (as soon as I get my rig in order). The Hitman games were also a bit "iffy" in some parts, but I enjoyed them and think they are great games. The same goes for STALKER.
Eidos must have thought their bribes were not good enough. I bet one of the arguments involved Oblivion and Bethesda's way of handling bribes. They should hire Pete Hines (or at least learn how it's done from him).