When you, as a reviewer, give a game a 10 you have just proven that you are worthless not only as a game reviewer but as a human being in general. In fact, you are required, by law, to delete your GameJournalismDiploma.PDF that you downloaded. Sorry, but that's the way it is.
Halo 3 is not a 10/10 game. Bioshock is not a 10/10 game. Anyone who is trying to tell you that it is, is a filthy lying idiot.
For a game to be a 10, it must be of unapproachable perfection. It must contain such perfectly executed code that it can only be engraved on discs made from the purest platinum. A disc that contained such code would be so bright that you could not directly look at it without your head exploding in a cloud of blood from the sheer potential euphoria that it emits. In fact, upon inserting said disc into the console, you would instantly ejaculate. If this does not happen, it's not a perfect game.
Also, playing the game would be a continuous 90 hour orgasm, which would be at least seven times more powerful than being fellated by Jessica Alba, Jessica Rabbit and Jessica Chobot, as well as Ada Wong simultaneously, while playing a 25x25 grid of Picross.
Also the game would be designed by Will Wright, Sid Meier, Alexey Pazhitnov, Hideo Kojima and Miyamoto; contain the characters Marcus Fenix, Cloud Strife, the "L" Tetris block, Yoshi and Kratos; have music by Howard Shore remixed by Paul Oakenfold then remixed again by DJ Jazzy Jeff; be directed by Peter Jackson, Ridley Scott, George Lucas and Stanley Kubrick and then fucked around by George Lucas again; be written by J.R.R. Tolkien in collaboration with Tom Clancy and Stephen King and then plagiarized by Clive Barker. The game would also start you off as an organism, which evolves through every possible stage of life including every human and alien civilization both known and unknown, with elements of stealth-action through each epoch using a shadow meter; has tactical strategy that is real-time with the option to pause play so you can queue up your spells, has deep puzzle solving elements where you can beat up hookers with bats with none of that platform jumping bullshit, include a deep well-rounded RPG experience in between frenetic first-person-over-the-shoulder-run-and-gun fireplay with hundreds of doves flying in slow motion. And the game is controlled entirely with two Wiimotes, one in each hand. And it's in Dolby Pro Logic II. And your girlfriend can play with you simultaneosly. And it's not too hard for her.
After completing such a perfect game, your Wii console would instantly explode emitting a powerful EMP which permanently disrupts all electronics, especially Playstation 3's and Xbox360's within a 900 mile radius. If this does not happen, it's not a perfect game.
Also, the game could only be reviewed by Matt Casamassina, who would, upon bestowing the ultimate 10 out of 10 score, and realizing with horror that there would be no further use for his continued existence, cause his own head to explode in a cloud of blood. It would be a sad day because we love that fucking guy.
Also, at that precise moment, radiating out of Reggie Fils-Aime would be waves of orgasmic satisfaction, the force of which would not only sink the entire country of China, and ridding the entire world of software pirates forever, but also sending Perrin Kaplan into massive, mouth-frothing conniption which also causes her head to explode in a cloud of blood, because Reggie is fucking awesome! That man eats doors!
As a footnote, if Peter Molyneux is at all involved, or if he is even within 39 time zones of the game being developed, the game instantly fails. In fact, the game could not possibly achieve more than a 3.5 out of 10.
...come to think of it, that would be a pretty awesome game.