Halo. (1-... whatever)
I apologize in advance by offending anyone, but in my eyes there's no game hyped up more than Halo that has been such a disappointment. I played the original Halo when it came out, HATED the campaign. I hated the weapons, hated the enemies, hated the AI, and uh ... well that covers most of it. The story was admittedly pretty interesting at first, and the soundtrack was pretty beautiful. Beyond that I thought it was utter crap. I didn't feel like the combat was evolved that much at all from other shooters I was playing at the time. Yes the multiplayer was fun for a bit, but I'm not the kind of person that really wants to play a game just for multiplayer *eyes Black Ops*.
Years pass, I began to feel bad and thought that I may be overlooking something. I watch some video reviews and try out a Halo 3 campaign round with a buddy. Best Halo game to date with online with a friend, can't go wrong! Man was I wrong. The first level was a joke. The baddies were annoying as hell, the cover was terrible, the weapons all sucked in my opinion, the ammo was scarce ... it took the two of us on normal about an hour and a half to get to the first attacked base or whatever only to get slaughtered over and over. And the graphics were nothing to brag about as far as I could tell. I know there were a few releases before Halo 3 that had way better graphics than that. It seemed stale.
Based on those two first impressions, I don't want to touch a Halo game in my life again. The hype makes me want to vomit. If people praise this garbage to be paving the way of games in the future, I want to throw my controller at my TV.
From what I can tell though, the worst games are the over-hyped games. The best games are always the underdogs striving to get the name out. You didn't see huge ad campaigns for games like Psychonauts, Shadow of the Colossus, the Thief series, Adventures of Lolo *cough*, or even Magicka for example. Yet to me these are hands down some of the best games I have ever experienced. Sure, some of the hyped games may be good in some aspects, but rarely in my personal experience are they as memorable as the underdogs.