If it was up to me it would be this:
Below 50 - Varying degrees of garbage...from "unplayable" all the way to "playable but why are you wasting your time on it when there are better games out there?"
50-60 - A decent game, but possibly riddled with technical glitches, bad controls, mediocre graphics.......or it's just not that great of a game with no "wow factor" or original concept at all.
60-70 - A fun game in the right hands, but like the above, may have some technical issues, or just a shitty boring story...and no fun gimmicky new concept or features.
70-80 - A VERY fun game in the right hands, but outside of those right hands its just kind of good but nothing special. A must get for a fan of the specific genre it's in, but otherwise it's skippable. Or could be a sequel to an 80+ type game that does nothing to move the series forward, a half-assed effort on what could have been great.
80-85 - At this point should be technical issue free, or an issue so minor a post-launch patch fixes it up nice. A unanimously great game, but just not quite for everyone....wouldn't get a score below a 70 (unless some random reviewer just hated it) but would get some in the 70's that bring it down to the low 80's.
85-90 - Issue free from launch, good graphics, good replayablity, virtually anyone who picks it up would enjoy it. A game with this score should stand up as one of the best of the generation.
90-95 - An amazing game. A technical achievement, everyone and their grandmother would like it. Tons of replayability, some type of really cool original concept (or if it's not super original it at least improves greatly on what it's copying)...A must buy for anyone.
95-100 - A masterpiece. Only games like Ocarina of Time, Uncharted 2, GTA IV/V, Super Mario 64, Pokemon Red/Blue, etc. etc. you get the idea...games of amazing calibre that you should buy 2 copies of just in case the first disc gets scratched and it's too late at night to go to the game store...you need that extra copy because the game is so fucking good you can't miss out on any chance to play it.
