One definition of a review is “...a report or essay giving a critical estimate of a work or performance...” How do you as a reviewer accomplish this? If you are reviewing a house, you would for example, examine the location, space and house condition. By setting criteria on what you based your review on, you can compare your a review of one house with another. This is one of the most crucial aspects of a review, to make a valid comparison.
While a review is arguably an opinion of the reviewer, it is however has to be based how the work or performance fares against a set of criteria. One cannot simply rate a house that is located in amazing location, large living area and in perfect condition, lower scores because the reviewer does not like to live a posh neighborhood.
With games, respected site like IGN for example has the following criteria, Presentation, Graphic, Sound, Gameplay and Lasting Appeal.
Let’s examine Metal Gear Solid 4.
Presentation. A quote from IGN itself, “...A story worthy of a feature length film, with action that keeps you engaged from the second you hit the start button 'til the final credits roll....” While a reviewer may prefer sci-fi theme to real-world theme, a reviewer should always set aside this preference while reviewing a game. The presentation in MGS4 is arguably better to games like Mass Effect and Uncharted, both which received 9 from IGN itself. Some may prefer the presentation of Mass Effect to MGS4, however one simply cannot score MGS4 presentation lower to Mass Effect or Uncharted.
Graphic. Graphic in MGS4 is simply solid. The game has high quality textures, amazing details and superb animations. It is by far the best graphic ever in Playstation, only Uncharted is coming really close to it (9.5). Let’s compare this to Mass Effect, IGN rated Mass Effect graphic as 8.5. The graphic in Mass Effect is good, however with of course noticeable issues. By just using these two reviews, one simply cannot score MGS4 graphic lower than 9-9.5. At 8.5 the reviewer will basically argue that MGS4 graphic is the same as Mass Effect, which of course ludicrous.
Sound. It is simply masterpiece. The voice over is simply outstanding. The soundtrack is moving. Again comparable to Mass Effect, GTA4 and Uncharted, which all received a score of 9.5-10. Based on this, MGS4 score in sound should at least equal or higher compare to those games, 9.5-10.
Gameplay. MGS4 allow you to play stealthily or you can always blazing your way through with a choice of at least two dozen weapons. CQC in game is unique as well complex. There are multiple ways you can clear an area. By comparison, Mass Effect with its score of 9 in gameplay, has incredibly fun and deep combat system. One cannot simply rated MGS4 gameplay lower than Mass Effect score.
Lasting Appeal. MGS4 offers plenty of Easter Eggs, high replayability and most importantly a free MGO. MGO offers player unlimited replayability in multiplayer gaming. Mass Effect which has high replayability however with no multiplayer received a score of 9 from IGN.
Based on those criteria alone, a reviewer would have to present a very strong argument to score MGS4 lower than those games. Just adding the scores, MGS4 should have at least received a combined score of around 9-9.5 at the minimum; any lower than that then the review is no longer a review but simply an unfounded opinion.