Why do reviewers think themselves justified in revealing game secrets? Do they think that the best way to describe a game's twisting plotlines or hidden surprises is to simply reveal a few of them?
There may be some truth in that, but it's just woeful review etiquette in my book. It is totally possible to review a game without revealing its secrets or too much about where the adventure leads; if you can't then you're obviously relying too much on the game to review itself. You can sufficiently talk about and critique a game without revealing what happens in it.
Even on a small scale this can be annoying. A secret here, a location there; I don't think reviewers appreciate how little the reader needs to extrapolate the truth (or, even worse, false assumptions) from even the tinniest info slippage.
What really pisses me off is people who think they are being wily by saying "After about 4 hours of gameplay something REALLY BIG happens that changes the game completely", or, "Without wanting to give it away, there are a few key deaths across the epic story". That's not better! Any reasonably switched-on player will then immediately be looking out for these things during play, which undercuts almost any major surprise the game can throw at them.
I was going to illustrate my point with an example from a recent game, but I won't. In fact, I won't even name the game through fear of association with either of the above spoiler examples. I've got a little more respect for readers.