Valve is overhauling Steam’s user review system in an effort to remove submissions for games that were acquired using Steam product keys. The company says the reason for the move is to stop those developers who “are willing to employ deceptive tactics to generate a more positive review score.”

Additionally, a new set of filters that have been introduced that will let users view reviews by language, purchase source (Steam/Key activation/both), and whether it is positive, negative or both.

While it is still possible to see summaries from those who acquired a game using a product key from either a third-party website or a developer, the overall review score will now be based only on purchases made directly through Steam.

An analysis of games across Steam shows that at least 160 titles have a substantially greater percentage of positive reviews by users that activated the product with a cd key, compared to customers that purchased the game directly on Steam. There are, of course, legitimate reasons why this could be true for a game: Some games have strong audiences off Steam, and some games have passionate early adopters or Kickstarter backers that are much more invested in the game.

But in many cases, the abuse is clear and obvious, such as duplicated and/or generated reviews in large batches, or reviews from accounts linked to the developer. In those cases, we've now taken action by banning the false reviews and will be ending business relationships with developers that continue violating our rules.

For many titles, the smallest difference in the review score can see their rating change from positive to mixed.

As noted by, the move has already resulted in a change of the review score category for around 14 percent of games on Steam, and could spell bad news for honest indie developers such as Simon Roth, whose Maia game has seen its score drop to 45 percent following the update.

Valve also plans to filter out joke reviews that get marked as “helpful" simply because they are funny. The company says these posts do not give an indication of whether or not you should buy the game, and therefore aren’t actually helpful.