Review Scores Are Mostly Meaningless

Just like Me and Zero Punctuation everybody seems to be in agreement that Portal is a vastly superior game than Halfe Life 2 Episode Two in ValVe's Orange Box.

Portal is an amazingly fun game with fresh gameplay, where as Episode Two is just more of the same tired gameplay. Yet MetaCritic gives Half Life 2 Episode 2 a MetaCritic Score of (currently) 91 and Portal gets a MetaCritic Score of (currently) 89. Which means that the review scores both games have been getting are a direct contradiction to what people have been saying about them. IGN gave Portal an 8.2 and Episode 2 a 9.2 with an Editor's Choice Award yet on their Podcasts just like everybody else, they have been gushing about Portal.

So if Portal > Half Life 2 Episode 2, then why isn't Portal's review scores!?