Games don't really have much journalism. The Escapist sometimes posts real journalism, like announcing plans for a sequel to something, what Bobby Kotick's salary is, etc. But beyond stuff like that, games don't really have journalism. They have reviews, but those are opinion pieces, and in any other sphere of entertainment, reviewers can do whatever they damn well please--reviews can be bad or misleading, but they can't really be 'corrupt'.
Of course, that's all how it would be if things actually worked how they were supposed to. In gaming, people look at reviews as if they're supposed to be some sort of buyer's guide, an unbiased service to the consumer. They aren't, but publishers and marketing departments are more than happy to exploit this notion--after all, why wouldn't they? Gamers already treat reviews as marketing. The problem of 'corruption' stems from a flawed set of expectations, and it's on the consumers to start actually treating reviews as critique, which will take power away from 'corrupt' reviewers--those who take money to give good reviews--and give more power to reviewers who actually have an interesting voice and something to say. Placing responsibility on reviewers and publishers to be less 'corrupt' won't work, because you're essentially telling them not to do their jobs.