Hardcore Halo fan Quint at Ain't It Cool News tells his story of his Halo love affair and how he got to play Halo 3. It's not so much a review, but he does have this to say:

The graphics are great, too. The landscapes are massive and incredibly detailed. It’s not as stylistic as something like Bioshock, but if it had been it wouldn’t have felt like Halo. Here you get a look at future African landscape, war-torn and under invasion and then a little later on you get more traditional alien levels.

Quint particulalry liked skulls and saved films.