I think that the written portion of the review is ok, although it's pretty obvious how much the reviewer hated XIII and wanted to hate XIII-2. Regardless, the problem is how the reviewer adheres (or does not adhere) to their review system methodology.
For example, under gamrReview's methodology, a score between 5-5.9 is:
"Mediocre. These games are bland and ordinary. They barely make adequate status, and will likely not be particularly enjoyable if at all. Note that we do not expect the “average” game to fall into this range. Ideally most people are making games that are at least good, and the majority of games do not need to be scored in this range or below."
If the review score was in the 7 (or hell, even the 6 range), then it would match the methodology given by gamrReview, but a 5.4 just doesn't seem to match the game, especially considering that many have enjoyed it thus far.
Beyond the score, it's also important to note that while reviews are opinions, they are supposed to reflect how the reviewer believes other gamers would recieve a particular game, which is evident in the methodology (in the methodology, terms like "most people" are used). Thus, even if the reviewer hates a particular game, they have to review a game based on how he or she perceives others would recieve it. Generability is one of the major factors that separate a well-written review from a mere opinion piece, and if you can't write a review under that notion, then you really shouldn't be writing an official review.
I have no problem with a heavily-biased individual reviewing a game that he or she hates, as long as that reviewer abides by the methodology given by their review system. When reviewers don't follow their site's own methodology, it's hard to take those reviewers seriously.
