Louis Wu at HBO sifted through Blue's News and found a couple of reviews that escaped attention earlier:

Game Revolution gave Halo an A grade in their review; about the only thing they didn't like was the lack of bots.

Game Nation gave Halo a rating of 96, and strangely enough cited lack of story involvement as a con. Interesting.

XboxWeb put up another review, although their rating remained the same. However, Louis warns that the screenshots that accompany this version contain spoiler content.