I noticed that the IFWiki now has extensive links to past competition reviews, starting with 1998. Go here, click the year at the top, and then just scroll down to the review links. Also, Brass Lantern has archived many reviews here.
One of my all-time favorites – each IFComp 1999 game reviewed by one of the other games – is here. I remember really getting a big kick out of this the first time I read through it. The author, Dave Coleman, did a great job of capturing the essence of the “reviewing” and the “reviewed” game both. This was attempted by somebody else at least once in a future year, but it didn’t really work the way this one did.