Valve has updated how Steam handles user reviews today in a way that will affect how paid/free reviews affect the game’s overall score. Starting today, the review score will no longer be affected by users that received the game for free, including free weekends and gifts.
With the changes we are making now, the review score (shown at the top of store pages and in various places throughout the store such as search results) will no longer include reviews by users that received the game for free, such as via a gift, or during a free weekend. Reviews can still be written by customers that obtained the game in any of these ways, but the review will not count toward the overall review score.
Free to play games will not be affected by this change.