It depends.
Its not secret that Brink was hyped to hell and back about 50 million times, same thing with Dragon Age 2. And whilst they were (based upon what I've generally heard, I can't be sure as I haven't played either of em) overall good games their own hype sort of killed them.
I reckon if they weren't hyped up so much they would have been less critisised, though thats probably stating the obvious.
However then theres a game like Dead Space 2. It was hyped a fair bit but probably not as much as the other two above, and it came out, was awesome, and was pretty well received by both the players and the critics.
Then theres games that come out of nowhere with very little hype and become blockbusters, like Borderlands.
So it basically sorta seems to be something like this;
Game with lots of hype, turns out to be great upon release - Instant hit
Game with lots of hype, turns out be considerably worse than expectations but overwise ok - Both liked and hated. Usually mostly hated.
Game with little hype, turns out to be really damn good - Close to the level of an instant hit.
Game with little hype, turns out to be average or unnoteworthy upon release - Sinks into the ever expanding library of long forgotten games.
I don't think a game's hype has every ruined it for me personally, except for Halo Reach.
I remember popping the disk in hoping that its campaign would be good, based upon what was sort of indicated prior to release. Then I remember playing it and realising its campaign managed to be even less entertaining than Halo 3's, but it was probably my own damn fault for expecting a game with both single and multiplayer modes to have an at least half decent campaign.
Good thing the multiplayer turned out to be pretty cool though.