PSM3 have recently reviewed Uncharted 2 and given it a score of 21/20 to display how it has raised the stakes in what a video game can offer.
Some people believe that it isn't possible for Uncharted 2 to score "21/20" because a game can't be more "perfect" than perfect. But I don't believe any game review is based on perfection, because perfection simply doesn't exist.
I believe game reviews are based on perception. Here's an explanation.
Pong once was the only video game available. Therefore it would receive "5/5" or "10/10" or "20/20" if we were to review it. Why? Because it was the best game available, considering the state of the video game industry(or lack thereof) during its release.
But as more and more games are released, our perception of what "5/5" or "10/10" or "20/20" changes.
Even though our perception changes, we can't go back on our review of Pong and give it a lower score. Why? Because its score is still correct relative to its position in the timeline of videogames.
PSM3's numerical rating system will remain "20/20". They also won't mark down any points for games that were reviewed before Uncharted 2. Instead, they'll simply change what the new "20/20" means for FUTURE games.
All games reviewed by PSM3 from now on will be judged by what Uncharted 2 was able to deliver.
"21/20" for any videogame is basically a representation that it was able to change the perception of what the future "20/20" will be.
Hopefully those of you who read this will understand what I'm trying to say.