The problem is that there is no criteria or backing for how game review scores are calculated. Why is this a 9? Why was X a 5? Why was that other game a perfect 10? All the reviews done by just about every single company and every single person is all opinion with weird made up criteria. Just look at the end of IGN review videos. Their summation sections are like "Good visuals, lengthy story, but bad glitch halfway through the game." Then look at some other game they review. "Awesome character development, great story, but bad controls." It's like... Okay you're clearly making up different categories for every single fucking game you review. These scores have no criteria or backing to what they mean.
Game reviews should work like this:
1) Have SET CRITERIA for each genre of game. Shooters have a set number of categories that they get scored on. Examples would be graphics, gunplay, balance, replay-ability, depth, etc...
2) A different genre such as ADVENTURE would have a different set of categories that would get scored upon. Examples would be graphics, story, character development, pacing, fluidity, etc... The retro "indie" sort of genre wouldn't have a graphics category, but most modern games probably would.
3) Put WEIGHTS for each category. For example, story may be worth 30% of the score in an adventure game, while graphics may only be worth 15% of the score. So the number you give that category out of 10 will weigh correctly on the score.
4) Use these as standards across every game. This will eliminate bias. Furthermore, you could even ask several people within the company to complete the game and give their scores on the categories. This would give a larger sample size and remove bias even further from the game's score.
I really don't understand how massive companies like IGN still review games in the same old shitty way. Game reviews can be MASSIVELY improved upon with a simple standardized system, and having more than one person give their score on the game. Are they really so busy at IGN that only ONE person can review Uncharted 4? Surely they could have at least 3 people play the game, score it, and average those scores... Would give the review at least a little bit of credit.