5- The game has to be totally flawless graphically, relative to the time of release. Games like Wolfenstein 3d or Final Fantasy 7 that totally redefined the graphical norm get this rating.
4- Spectacular graphics that are either slightly rough or dated.
3- Average by the current standards. Either flawed implementation or looks just like 5s did last year. Duke Nukem or Alpha Centauri are the type of "nice but not great" that would get 3s.
2- The flaws or outdatedness of the graphics are distractingly apparent, to the point where the game is less enjoyable because of them.
1- The graphics are so bad that the game is only playable with effort to ignore them.
0- The game is either unplayable because of the graphics (Descent to Undermountain) or brain damage-inducing (Turok).
5- The sound both fully utilizes the current systems' capabilities and is well composed. Voice acting is superb, sound effects are as realistic as possible. Games like Final Fantasy 6 or The Neverhood get 5s.
4- Sound is still top-notch, but with a few noticeable flaws (one particular bad voice actor, a couple sound effects off, a particularly irritating piece of background music).
3- Game is average soundwise. Score is generic, voice acting is passable but not particularly believable, sound effects are run-of-the-mill. Practically any first person shooter will end up here.
2- Sub par sound. Music is repetitive and poorly arranged, voice acting sounds like it's being read off, sound effects are blatantly computer-made.
1- Generally play with the sound off. Insanely repititious music or soundtrack of pop hits from two years ago, voice acting courtesy of some bums they found on the street, sound effects lifted from Ed Wood movies.
0- The game is totally unplayable with the sound on. I can't think of any games that were actually this terrible, but BOKOSUKA WARS for NES and the first couple Ultimas came awfully close.
5- The interface is totally intuitive and perfect for the type of game. Games with incredibly complex settings that manage everything smoothly (Homeworld) or with very quick gameplay that still manage to make many options accessible (Diablo 2) get 5s.
4- Interface is intuitive and slick, but has occasional annoying glitches.
3- Generally solid interface, but with enough minor problems or lack of options that it interferes with gameplay on occasion. The bizarre camera in Myth or the "Please Try That Click Again" spazziness of Bloodnet earn them 3s.
2- Interface is flawed to the point of making parts of the game difficult. Platform games with loose controls or hideously complex sims come to mind.
1- Fundementally flawed interface. Impossible to play the game without constantly having to overcome the interface problems.
0- Game is unplayable because the interface is so godawful. Free D.C., I'm talking to you.
Replay Value (0-5)
5- You keep playing the game for years, generally until it's supplanted by an equally great sequel. Civilization (1 and 2, not 3), Master of Orion 2, Final Fantasy 1, 5, and 6, and Tekken 3 are all examples of games that get 5s. Alternately, the game could offer multiplayer that never gets old, like Starcraft or Unreal.
4- You play the game excessively, uninstall it, reinstall it six months later to play some more. Repeat ad infinitum.
3- Average replayability. Might play through the game a few times, and install it once again for nostalgia's sake in the future. Baldur's Gate or Command and Conquer are examples.
2- Fairly short lived appeal. By the second time you play through the game it's starting to get boring.
1- No replayability. After you've played the game through once there's no reason to even consider playing it again.
0- No replayability, plus it's insanely short. Think any early NES game that didn't at least have a score to beat, or The Sims (ha ha... I am only kidding... please don't send me hate mail, simspeople).
This is a little more subjective scale. A 15 is a game that is aesthetically perfect; a game in which you can't find a single flaw, ignoring those covered by the other categories. If you can play through an entire game without having a single complaint about how the game was designed, it's a 15. My general rule is to subtract 1 for each minor complaint and 2+ for each major complaint. A game with a 0 had better be something like pressing the "-" key to change the colors of random pixels on the screen.
The game doesn't have to be complex. Perfectly designed Tetris is a 15, as is perfectly designed but vastly more complex Starcraft.
Enjoyment is the counterpart to gameplay. Some games are designed painstakingly well, but seem to be designed for some alternate-world humans who enjoy different things than the humans of this world. Black and White is a design marvel. Do most people ENJOY Black and White? No. A 15 enjoyment means you had fun playing the game, period. Arcade games can manage to have top-notch enjoyment even if they'e lacking in every other category. As a guideline, I start with 15 enjoyment and subtract any time the game does something to dampen my mood.
A simple way of looking at gameplay and enjoyment: If a game is FUN to play it's got a high enjoyment. If a game is SATISFYING to play, it has high gameplay.
Add up all those numbers, multiply *.2 and you have your final 0-10 score.
I give a couple extra scores which are just for fun:
Change (----- to +++++)
This is exclusively for sequels. -s means it's worse than the predecessor, +s mean it's better. ----- means the game is so much worse that it's totally destroyed the predecessor's good name. Think Jet Moto 2, or Actraiser 2. +++++ means it was so phenomenally good that it pulled an obscure franchise into the limelight. Heroes of Might and Magic 2 or Warcraft 2 are examples of this. In between means that it got marginally better or worse, and 0 means it's same old, same old.
Swear word rating (swear frequency)
Just how much the game makes me curse. Sometimes a measure of the game being challenging (most fighting games on high levels) or frustratingly poorly designed (Civ 3 had a rating of over 10 Goddamnits Per Minute (GPM)).
This community isn't exclusively my domain. I want to add as many qualified reviewers as possible, and I don't expect them to follow my reviewing scheme mindlessly. If you think you're qualified and would like to be a part of the community, just send me a sample review and I'll consider it. I don't care how much people post. It doesn't matter if you buy a game a week or a game a year. The deciding factors are levelheadedness, insight, and entertaining rhetoric.