Well, first of all when we review we don't have a standard weight for different factors. Some games require certain things more than others. For example, replay value is a non-factor in a P&C game, but a huge factor in a shooter which needs good multiplayer.
We divide things up in 3 basic categories with gameplay, presentation, and value. Presentation covers graphics, story, sound, characters, etc. We don't score these individually, but we do address their individual quality in the text. These again do not have equal weights. Certain games require heavier focus on one or more of these categories.
My biggest tip as the senior editor in charge of the reviews on this site is: Be complete, review each game for its individual merits, and never forget your target audience.
