Fun is so extremely subjective that some people play DESTINY and CoD for fun, it's difficult to quantify in the time frame that reviewers are held to for each video game
Japanese game magazines use a collaborative scoring system for game reviews. 4 editors provide individual ratings and personal opinion of the game, and a combined overall score which is simply a sum of the 4 scores.
The idea is to incorporate subjectivity into the reviews. Readers familiar with the editors would understand which score/opinion they can relate more to.